diff --git a/apps/sim/app/(auth)/signup/signup-form.tsx b/apps/sim/app/(auth)/signup/signup-form.tsx
index 5d1b2d25ff6..c721a07291b 100644
--- a/apps/sim/app/(auth)/signup/signup-form.tsx
+++ b/apps/sim/app/(auth)/signup/signup-form.tsx
@@ -10,6 +10,7 @@ import { usePostHog } from 'posthog-js/react'
 import { Input, Label } from '@/components/emcn'
 import { client, useSession } from '@/lib/auth/auth-client'
 import { getEnv, isFalsy, isTruthy } from '@/lib/core/config/env'
+import { validateCallbackUrl } from '@/lib/core/security/input-validation'
 import { cn } from '@/lib/core/utils/cn'
 import { quickValidateEmail } from '@/lib/messaging/email/validation'
 import { captureClientEvent, captureEvent } from '@/lib/posthog/client'
@@ -102,10 +103,14 @@ function SignupFormContent({ githubAvailable, googleAvailable, isProduction }: S
   useEffect(() => {
     setTurnstileSiteKey(getEnv('NEXT_PUBLIC_TURNSTILE_SITE_KEY'))
   }, [])
-  const redirectUrl = useMemo(
-    () => searchParams.get('redirect') || searchParams.get('callbackUrl') || '',
-    [searchParams]
-  )
+  const rawRedirectUrl = searchParams.get('redirect') || searchParams.get('callbackUrl') || ''
+  const isValidRedirectUrl = rawRedirectUrl ? validateCallbackUrl(rawRedirectUrl) : false
+  const invalidCallbackRef = useRef(false)
+  if (rawRedirectUrl && !isValidRedirectUrl && !invalidCallbackRef.current) {
+    invalidCallbackRef.current = true
+    logger.warn('Invalid callback URL detected and blocked:', { url: rawRedirectUrl })
+  }
+  const redirectUrl = isValidRedirectUrl ? rawRedirectUrl : ''
   const isInviteFlow = useMemo(
     () =>
       searchParams.get('invite_flow') === 'true' ||
diff --git a/apps/sim/app/(auth)/verify/use-verification.ts b/apps/sim/app/(auth)/verify/use-verification.ts
index 3ef05231a4e..ec95836c98a 100644
--- a/apps/sim/app/(auth)/verify/use-verification.ts
+++ b/apps/sim/app/(auth)/verify/use-verification.ts
@@ -4,6 +4,7 @@ import { useEffect, useState } from 'react'
 import { createLogger } from '@sim/logger'
 import { useRouter, useSearchParams } from 'next/navigation'
 import { client, useSession } from '@/lib/auth/auth-client'
+import { validateCallbackUrl } from '@/lib/core/security/input-validation'
 
 const logger = createLogger('useVerification')
 
@@ -55,8 +56,11 @@ export function useVerification({
       }
 
       const storedRedirectUrl = sessionStorage.getItem('inviteRedirectUrl')
-      if (storedRedirectUrl) {
+      if (storedRedirectUrl && validateCallbackUrl(storedRedirectUrl)) {
         setRedirectUrl(storedRedirectUrl)
+      } else if (storedRedirectUrl) {
+        logger.warn('Ignoring unsafe stored invite redirect URL', { url: storedRedirectUrl })
+        sessionStorage.removeItem('inviteRedirectUrl')
       }
 
       const storedIsInviteFlow = sessionStorage.getItem('isInviteFlow')
@@ -67,7 +71,11 @@ export function useVerification({
 
     const redirectParam = searchParams.get('redirectAfter')
     if (redirectParam) {
-      setRedirectUrl(redirectParam)
+      if (validateCallbackUrl(redirectParam)) {
+        setRedirectUrl(redirectParam)
+      } else {
+        logger.warn('Ignoring unsafe redirectAfter parameter', { url: redirectParam })
+      }
     }
 
     const inviteFlowParam = searchParams.get('invite_flow')
diff --git a/apps/sim/connectors/obsidian/obsidian.ts b/apps/sim/connectors/obsidian/obsidian.ts
index f8c469dc86a..bf570b96af1 100644
--- a/apps/sim/connectors/obsidian/obsidian.ts
+++ b/apps/sim/connectors/obsidian/obsidian.ts
@@ -1,6 +1,7 @@
 import { createLogger } from '@sim/logger'
 import { toError } from '@sim/utils/errors'
 import { ObsidianIcon } from '@/components/icons'
+import { validateExternalUrl } from '@/lib/core/security/input-validation'
 import { fetchWithRetry, VALIDATE_RETRY_OPTIONS } from '@/lib/knowledge/documents/utils'
 import type { ConnectorConfig, ExternalDocument, ExternalDocumentList } from '@/connectors/types'
 import { joinTagArray, parseTagDate } from '@/connectors/utils'
@@ -8,6 +9,7 @@ import { joinTagArray, parseTagDate } from '@/connectors/utils'
 const logger = createLogger('ObsidianConnector')
 
 const DOCS_PER_PAGE = 50
+const DEFAULT_VAULT_URL = 'https://127.0.0.1:27124'
 
 interface NoteJson {
   content: string
@@ -22,10 +24,29 @@ interface NoteJson {
 }
 
 /**
- * Normalizes the vault URL by removing trailing slashes.
+ * Normalizes the vault URL and validates it against SSRF protections.
+ *
+ * The Obsidian Local REST API plugin runs on the user's own machine, so there
+ * is no SaaS domain to allowlist — the vault URL is fully user-controlled. We
+ * defer to the shared `validateExternalUrl` policy:
+ *   - hosted Sim: blocks localhost, private IPs, HTTP (forces HTTPS)
+ *   - self-hosted Sim: allows http://localhost (built-in carve-out), still
+ *     blocks non-loopback private IPs and dangerous ports (22, 25, 3306,
+ *     5432, 6379, 27017, 9200)
+ *
+ * This does not defend against DNS rebinding; for hosted deployments the user
+ * must expose the plugin through a public URL (tunnel, port-forward).
  */
-function normalizeVaultUrl(url: string): string {
-  return url.trim().replace(/\/+$/, '')
+function resolveVaultEndpoint(rawUrl: string | undefined): string {
+  let url = (rawUrl || DEFAULT_VAULT_URL).trim().replace(/\/+$/, '')
+  if (url && !url.startsWith('https://') && !url.startsWith('http://')) {
+    url = `https://${url}`
+  }
+  const validation = validateExternalUrl(url, 'vaultUrl')
+  if (!validation.isValid) {
+    throw new Error(validation.error || 'Invalid vault URL')
+  }
+  return url
 }
 
 /**
@@ -61,9 +82,6 @@ async function listDirectory(
   return data.files ?? []
 }
 
-/**
- * Recursively lists all markdown files in the vault or a specific folder.
- */
 const MAX_RECURSION_DEPTH = 20
 
 async function listVaultFiles(
@@ -183,9 +201,7 @@ export const obsidianConnector: ConnectorConfig = {
     cursor?: string,
     syncContext?: Record<string, unknown>
   ): Promise<ExternalDocumentList> => {
-    const baseUrl = normalizeVaultUrl(
-      (sourceConfig.vaultUrl as string) || 'https://127.0.0.1:27124'
-    )
+    const baseUrl = resolveVaultEndpoint(sourceConfig.vaultUrl as string)
     const folderPath = (sourceConfig.folderPath as string) || ''
 
     let allFiles = syncContext?.allFiles as string[] | undefined
@@ -230,9 +246,7 @@ export const obsidianConnector: ConnectorConfig = {
     externalId: string,
     _syncContext?: Record<string, unknown>
   ): Promise<ExternalDocument | null> => {
-    const baseUrl = normalizeVaultUrl(
-      (sourceConfig.vaultUrl as string) || 'https://127.0.0.1:27124'
-    )
+    const baseUrl = resolveVaultEndpoint(sourceConfig.vaultUrl as string)
 
     try {
       const note = await fetchNote(baseUrl, accessToken, externalId)
@@ -275,7 +289,12 @@ export const obsidianConnector: ConnectorConfig = {
       return { valid: false, error: 'Vault URL is required' }
     }
 
-    const baseUrl = normalizeVaultUrl(rawUrl)
+    let baseUrl: string
+    try {
+      baseUrl = resolveVaultEndpoint(rawUrl)
+    } catch (error) {
+      return { valid: false, error: toError(error).message }
+    }
 
     try {
       const response = await fetchWithRetry(
@@ -313,8 +332,10 @@ export const obsidianConnector: ConnectorConfig = {
 
       return { valid: true }
     } catch (error) {
-      const message = error instanceof Error ? error.message : 'Failed to connect to Obsidian vault'
-      return { valid: false, error: message }
+      return {
+        valid: false,
+        error: toError(error).message || 'Failed to connect to Obsidian vault',
+      }
     }
   },
 
diff --git a/apps/sim/connectors/servicenow/servicenow.ts b/apps/sim/connectors/servicenow/servicenow.ts
index be55c08ae98..86f6a40617b 100644
--- a/apps/sim/connectors/servicenow/servicenow.ts
+++ b/apps/sim/connectors/servicenow/servicenow.ts
@@ -1,6 +1,7 @@
 import { createLogger } from '@sim/logger'
 import { toError } from '@sim/utils/errors'
 import { ServiceNowIcon } from '@/components/icons'
+import { validateServiceNowInstanceUrl } from '@/lib/core/security/input-validation'
 import { fetchWithRetry, VALIDATE_RETRY_OPTIONS } from '@/lib/knowledge/documents/utils'
 import type { ConnectorConfig, ExternalDocument, ExternalDocumentList } from '@/connectors/types'
 import { htmlToPlainText, parseTagDate } from '@/connectors/utils'
@@ -45,15 +46,23 @@ interface Incident extends ServiceNowRecord {
 }
 
 /**
- * Normalizes the instance URL to ensure it has the correct format.
+ * Normalizes and validates the ServiceNow instance URL.
+ *
+ * Prepends https:// if the scheme is missing, strips trailing slashes, then
+ * enforces a ServiceNow-owned domain allowlist to prevent SSRF — the instance
+ * URL is user-controlled and was previously fetched server-side with no
+ * validation.
  */
-function normalizeInstanceUrl(instanceUrl: string): string {
-  let url = instanceUrl.trim()
-  url = url.replace(/\/+$/, '')
-  if (!url.startsWith('https://') && !url.startsWith('http://')) {
+function resolveServiceNowInstanceUrl(rawUrl: string): string {
+  let url = (rawUrl ?? '').trim().replace(/\/+$/, '')
+  if (url && !url.startsWith('https://') && !url.startsWith('http://')) {
     url = `https://${url}`
   }
-  return url
+  const validation = validateServiceNowInstanceUrl(url)
+  if (!validation.isValid) {
+    throw new Error(validation.error || 'Invalid instance URL')
+  }
+  return validation.sanitized ?? url
 }
 
 /**
@@ -430,7 +439,7 @@ export const servicenowConnector: ConnectorConfig = {
     cursor?: string,
     _syncContext?: Record<string, unknown>
   ): Promise<ExternalDocumentList> => {
-    const instanceUrl = normalizeInstanceUrl(sourceConfig.instanceUrl as string)
+    const instanceUrl = resolveServiceNowInstanceUrl(sourceConfig.instanceUrl as string)
     const contentType = (sourceConfig.contentType as string) || 'kb_knowledge'
     const maxItems = sourceConfig.maxItems ? Number(sourceConfig.maxItems) : DEFAULT_MAX_ITEMS
     const authHeader = buildAuthHeader(accessToken, sourceConfig)
@@ -504,7 +513,6 @@ export const servicenowConnector: ConnectorConfig = {
     sourceConfig: Record<string, unknown>,
     externalId: string
   ): Promise<ExternalDocument | null> => {
-    const instanceUrl = normalizeInstanceUrl(sourceConfig.instanceUrl as string)
     const contentType = (sourceConfig.contentType as string) || 'kb_knowledge'
     const authHeader = buildAuthHeader(accessToken, sourceConfig)
     const isKB = contentType === 'kb_knowledge'
@@ -514,6 +522,8 @@ export const servicenowConnector: ConnectorConfig = {
       ? 'sys_id,short_description,text,wiki,workflow_state,kb_category,kb_knowledge_base,number,author,sys_created_by,sys_updated_by,sys_updated_on,sys_created_on'
       : 'sys_id,number,short_description,description,state,priority,category,assigned_to,opened_by,close_notes,resolution_notes,sys_created_by,sys_updated_by,sys_updated_on,sys_created_on'
 
+    const instanceUrl = resolveServiceNowInstanceUrl(sourceConfig.instanceUrl as string)
+
     try {
       const { result } = await serviceNowApiGet(instanceUrl, tableName, authHeader, {
         sysparm_query: `sys_id=${externalId}`,
@@ -568,7 +578,13 @@ export const servicenowConnector: ConnectorConfig = {
       return { valid: false, error: 'Max items must be a positive number' }
     }
 
-    const normalizedUrl = normalizeInstanceUrl(instanceUrl)
+    let normalizedUrl: string
+    try {
+      normalizedUrl = resolveServiceNowInstanceUrl(instanceUrl)
+    } catch (error) {
+      return { valid: false, error: toError(error).message }
+    }
+
     const authHeader = buildAuthHeader(accessToken, sourceConfig)
     const tableName = contentType === 'kb_knowledge' ? 'kb_knowledge' : 'incident'
 
@@ -585,8 +601,7 @@ export const servicenowConnector: ConnectorConfig = {
       )
       return { valid: true }
     } catch (error) {
-      const message = error instanceof Error ? error.message : 'Failed to connect to ServiceNow'
-      return { valid: false, error: message }
+      return { valid: false, error: toError(error).message || 'Failed to connect to ServiceNow' }
     }
   },
 
diff --git a/apps/sim/lib/core/security/input-validation.test.ts b/apps/sim/lib/core/security/input-validation.test.ts
index 4086ee5341f..fb8dbf35d34 100644
--- a/apps/sim/lib/core/security/input-validation.test.ts
+++ b/apps/sim/lib/core/security/input-validation.test.ts
@@ -1,9 +1,10 @@
 import { featureFlagsMock } from '@sim/testing'
-import { describe, expect, it, vi } from 'vitest'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
 import {
   validateAirtableId,
   validateAlphanumericId,
   validateAwsRegion,
+  validateCallbackUrl,
   validateEnum,
   validateExternalUrl,
   validateFileExtension,
@@ -21,7 +22,9 @@ import {
   validatePathSegment,
   validateProxyUrl,
   validateS3BucketName,
+  validateServiceNowInstanceUrl,
   validateSupabaseProjectId,
+  validateWorkdayTenantUrl,
 } from '@/lib/core/security/input-validation'
 import { validateUrlWithDNS } from '@/lib/core/security/input-validation.server'
 import { sanitizeForLogging } from '@/lib/core/security/redaction'
@@ -1837,3 +1840,271 @@ describe('validateMondayColumnId', () => {
     })
   })
 })
+
+describe('validateCallbackUrl', () => {
+  const ORIGIN = 'https://sim.app'
+  const originalWindow = (globalThis as { window?: unknown }).window
+
+  beforeEach(() => {
+    ;(globalThis as { window?: unknown }).window = {
+      location: { origin: ORIGIN },
+    }
+  })
+
+  afterEach(() => {
+    if (originalWindow === undefined) {
+      ;(globalThis as { window?: unknown }).window = undefined
+    } else {
+      ;(globalThis as { window?: unknown }).window = originalWindow
+    }
+  })
+
+  describe('accepts legitimate same-origin URLs', () => {
+    it.each([
+      ['/workspace'],
+      ['/invite/abc-123'],
+      ['/invite/abc?foo=bar&baz=qux'],
+      ['/workspace#section'],
+      ['/credential-account/456'],
+      ['?reset=true'],
+      ['/'],
+      ['https://sim.app/workspace'],
+      ['https://sim.app/'],
+      ['HTTPS://SIM.APP/foo'],
+    ])('accepts %s', (url) => {
+      expect(validateCallbackUrl(url)).toBe(true)
+    })
+  })
+
+  describe('rejects open-redirect payloads', () => {
+    it.each([
+      ['', 'empty string'],
+      ['//evil.com', 'protocol-relative'],
+      ['/\\evil.com', 'backslash protocol-relative'],
+      ['\\\\evil.com', 'double backslash'],
+      ['/\t/evil.com', 'tab-stripped protocol-relative'],
+      ['/\n/evil.com', 'newline-stripped protocol-relative'],
+      ['/\r/evil.com', 'CR-stripped protocol-relative'],
+      ['https://evil.com', 'cross-origin absolute URL'],
+      ['https://sim.app@evil.com', 'userinfo smuggling'],
+      ['https://sim.app.evil.com', 'subdomain confusion'],
+      ['https://sim.app:3001/foo', 'different port'],
+      ['http://sim.app/foo', 'different protocol'],
+      ['javascript:alert(1)', 'javascript scheme'],
+      ['data:text/html,<script>alert(1)</script>', 'data scheme'],
+      ['vbscript:msgbox', 'vbscript scheme'],
+    ])('rejects %s (%s)', (url) => {
+      expect(validateCallbackUrl(url)).toBe(false)
+    })
+  })
+
+  describe('server-side (no window)', () => {
+    beforeEach(() => {
+      ;(globalThis as { window?: unknown }).window = undefined
+    })
+
+    it('falls back to placeholder origin and still rejects cross-origin URLs', () => {
+      expect(validateCallbackUrl('/workspace')).toBe(true)
+      expect(validateCallbackUrl('//evil.com')).toBe(false)
+      expect(validateCallbackUrl('https://evil.com')).toBe(false)
+      expect(validateCallbackUrl('javascript:alert(1)')).toBe(false)
+    })
+  })
+})
+
+describe('validateServiceNowInstanceUrl', () => {
+  describe('valid ServiceNow instance URLs', () => {
+    it.concurrent('should accept *.service-now.com', () => {
+      const result = validateServiceNowInstanceUrl('https://acme.service-now.com')
+      expect(result.isValid).toBe(true)
+      expect(result.sanitized).toBe('https://acme.service-now.com')
+    })
+
+    it.concurrent('should accept *.servicenow.com', () => {
+      const result = validateServiceNowInstanceUrl('https://acme.servicenow.com')
+      expect(result.isValid).toBe(true)
+    })
+
+    it.concurrent('should accept *.servicenowservices.com (GovCloud)', () => {
+      const result = validateServiceNowInstanceUrl('https://acme.servicenowservices.com')
+      expect(result.isValid).toBe(true)
+    })
+
+    it.concurrent('should accept URLs with paths', () => {
+      const result = validateServiceNowInstanceUrl('https://acme.service-now.com/api/now/table')
+      expect(result.isValid).toBe(true)
+    })
+
+    it.concurrent('should accept multi-level subdomains', () => {
+      const result = validateServiceNowInstanceUrl('https://dev.acme.service-now.com')
+      expect(result.isValid).toBe(true)
+    })
+  })
+
+  describe('invalid hosts — allowlist rejection', () => {
+    it.concurrent('should reject attacker-controlled domains', () => {
+      const result = validateServiceNowInstanceUrl('https://evil.com')
+      expect(result.isValid).toBe(false)
+      expect(result.error).toContain('ServiceNow-hosted domain')
+    })
+
+    it.concurrent('should reject lookalike suffixes', () => {
+      const result = validateServiceNowInstanceUrl('https://acme.service-now.com.evil.com')
+      expect(result.isValid).toBe(false)
+    })
+
+    it.concurrent('should reject embedded substrings', () => {
+      const result = validateServiceNowInstanceUrl('https://service-now.com.evil.com')
+      expect(result.isValid).toBe(false)
+    })
+
+    it.concurrent('should reject vanity CNAME hosts (Custom URL plugin)', () => {
+      const result = validateServiceNowInstanceUrl('https://support.acme.com')
+      expect(result.isValid).toBe(false)
+      expect(result.error).toContain('ServiceNow-hosted domain')
+    })
+
+    it.concurrent('should reject userinfo smuggling', () => {
+      const result = validateServiceNowInstanceUrl('https://acme.service-now.com@evil.com')
+      expect(result.isValid).toBe(false)
+    })
+  })
+
+  describe('invalid URLs — delegated to validateExternalUrl', () => {
+    it.concurrent('should reject null', () => {
+      const result = validateServiceNowInstanceUrl(null)
+      expect(result.isValid).toBe(false)
+    })
+
+    it.concurrent('should reject empty string', () => {
+      const result = validateServiceNowInstanceUrl('')
+      expect(result.isValid).toBe(false)
+    })
+
+    it.concurrent('should reject http:// protocol', () => {
+      const result = validateServiceNowInstanceUrl('http://acme.service-now.com')
+      expect(result.isValid).toBe(false)
+      expect(result.error).toContain('https://')
+    })
+
+    it.concurrent('should reject private IPs', () => {
+      const result = validateServiceNowInstanceUrl('https://192.168.1.1')
+      expect(result.isValid).toBe(false)
+      expect(result.error).toContain('private IP')
+    })
+
+    it.concurrent('should reject link-local metadata IP', () => {
+      const result = validateServiceNowInstanceUrl('https://169.254.169.254')
+      expect(result.isValid).toBe(false)
+    })
+
+    it.concurrent('should reject blocked ports', () => {
+      const result = validateServiceNowInstanceUrl('https://acme.service-now.com:22')
+      expect(result.isValid).toBe(false)
+      expect(result.error).toContain('blocked port')
+    })
+
+    it.concurrent('should reject malformed URLs', () => {
+      const result = validateServiceNowInstanceUrl('not-a-url')
+      expect(result.isValid).toBe(false)
+    })
+  })
+})
+
+describe('validateWorkdayTenantUrl', () => {
+  describe('valid Workday tenant URLs', () => {
+    it.concurrent('should accept *.workday.com implementation tenants', () => {
+      const result = validateWorkdayTenantUrl('https://wd2-impl-services1.workday.com')
+      expect(result.isValid).toBe(true)
+      expect(result.sanitized).toBe('https://wd2-impl-services1.workday.com')
+    })
+
+    it.concurrent('should accept *.workday.com production tenants', () => {
+      const result = validateWorkdayTenantUrl('https://wd5-services1.workday.com')
+      expect(result.isValid).toBe(true)
+    })
+
+    it.concurrent('should accept *.myworkday.com production tenants', () => {
+      const result = validateWorkdayTenantUrl('https://wd5-services1.myworkday.com')
+      expect(result.isValid).toBe(true)
+    })
+
+    it.concurrent('should accept URLs with trailing slash', () => {
+      const result = validateWorkdayTenantUrl('https://wd2-impl-services1.workday.com/')
+      expect(result.isValid).toBe(true)
+    })
+
+    it.concurrent('should be case-insensitive for hostname', () => {
+      const result = validateWorkdayTenantUrl('https://WD5-Services1.Workday.com')
+      expect(result.isValid).toBe(true)
+    })
+  })
+
+  describe('invalid hosts — allowlist rejection', () => {
+    it.concurrent('should reject attacker-controlled domains', () => {
+      const result = validateWorkdayTenantUrl('https://evil.com')
+      expect(result.isValid).toBe(false)
+      expect(result.error).toContain('Workday-hosted domain')
+    })
+
+    it.concurrent('should reject lookalike suffixes', () => {
+      const result = validateWorkdayTenantUrl('https://wd5.workday.com.evil.com')
+      expect(result.isValid).toBe(false)
+    })
+
+    it.concurrent('should reject embedded substrings', () => {
+      const result = validateWorkdayTenantUrl('https://workday.com.evil.com')
+      expect(result.isValid).toBe(false)
+    })
+
+    it.concurrent('should reject near-miss domains', () => {
+      const result = validateWorkdayTenantUrl('https://evilworkday.com')
+      expect(result.isValid).toBe(false)
+    })
+
+    it.concurrent('should reject userinfo smuggling', () => {
+      const result = validateWorkdayTenantUrl('https://wd5.workday.com@evil.com')
+      expect(result.isValid).toBe(false)
+    })
+  })
+
+  describe('invalid URLs — delegated to validateExternalUrl', () => {
+    it.concurrent('should reject null', () => {
+      const result = validateWorkdayTenantUrl(null)
+      expect(result.isValid).toBe(false)
+    })
+
+    it.concurrent('should reject empty string', () => {
+      const result = validateWorkdayTenantUrl('')
+      expect(result.isValid).toBe(false)
+    })
+
+    it.concurrent('should reject http:// protocol', () => {
+      const result = validateWorkdayTenantUrl('http://wd2-impl-services1.workday.com')
+      expect(result.isValid).toBe(false)
+      expect(result.error).toContain('https://')
+    })
+
+    it.concurrent('should reject private IPs', () => {
+      const result = validateWorkdayTenantUrl('https://192.168.1.1')
+      expect(result.isValid).toBe(false)
+      expect(result.error).toContain('private IP')
+    })
+
+    it.concurrent('should reject link-local metadata IP (SSRF classic)', () => {
+      const result = validateWorkdayTenantUrl('https://169.254.169.254')
+      expect(result.isValid).toBe(false)
+    })
+
+    it.concurrent('should reject blocked ports', () => {
+      const result = validateWorkdayTenantUrl('https://wd2-impl-services1.workday.com:22')
+      expect(result.isValid).toBe(false)
+      expect(result.error).toContain('blocked port')
+    })
+
+    it.concurrent('should reject malformed URLs', () => {
+      const result = validateWorkdayTenantUrl('not-a-url')
+      expect(result.isValid).toBe(false)
+    })
+  })
+})
diff --git a/apps/sim/lib/core/security/input-validation.ts b/apps/sim/lib/core/security/input-validation.ts
index 42cb49070e3..355bab8c28f 100644
--- a/apps/sim/lib/core/security/input-validation.ts
+++ b/apps/sim/lib/core/security/input-validation.ts
@@ -1155,23 +1155,40 @@ export function validatePaginationCursor(
   return { isValid: true, sanitized: value }
 }
 
+const CALLBACK_URL_SERVER_BASE = 'https://callback-url-validator.invalid'
+
 /**
  * Validates a callback URL to prevent open redirect attacks.
- * Accepts relative paths and absolute URLs matching the current origin.
+ *
+ * Accepts:
+ * - Same-origin relative references (e.g. `/workspace`, `/invite/abc?foo=bar`, `?q=1`)
+ * - Absolute URLs whose origin matches the current origin
+ *
+ * Rejects:
+ * - Cross-origin absolute URLs
+ * - Protocol-relative URLs (`//evil.com`) and backslash variants (`/\evil.com`,
+ *   `\\evil.com`), which browsers resolve to an external origin
+ * - Whitespace/control-character bypasses (`/\t/evil.com`, `/\n/evil.com`) — the
+ *   WHATWG URL parser strips these everywhere in the input, collapsing the value
+ *   to a protocol-relative reference
+ * - Userinfo smuggling (`https://trusted.com@evil.com`)
+ * - Opaque-origin schemes (`javascript:`, `data:`, `vbscript:`, etc.)
+ *
+ * Delegates parsing to `new URL()` so validation matches the browser's resolution
+ * when the value is later assigned to `window.location.href`. This mirrors the
+ * reference pattern from next-auth and follows the OWASP Unvalidated Redirects
+ * cheat sheet guidance to never validate URLs with string operations.
  *
  * @param url - The callback URL to validate
  * @returns true if the URL is safe to redirect to
  */
 export function validateCallbackUrl(url: string): boolean {
   try {
-    if (url.startsWith('/')) return true
-
-    if (typeof window === 'undefined') return false
+    if (typeof url !== 'string' || url.length === 0) return false
 
-    const currentOrigin = window.location.origin
-    if (url.startsWith(currentOrigin)) return true
-
-    return false
+    const base = typeof window === 'undefined' ? CALLBACK_URL_SERVER_BASE : window.location.origin
+    const parsed = new URL(url, base)
+    return parsed.origin === base
   } catch (error) {
     logger.error('Error validating callback URL:', { error, url })
     return false
@@ -1460,3 +1477,117 @@ export function isMicrosoftContentUrl(url: string): boolean {
     (suffix) => hostname === suffix || hostname.endsWith(`.${suffix}`)
   )
 }
+
+const SERVICENOW_ALLOWED_HOST_SUFFIXES = [
+  '.service-now.com',
+  '.servicenow.com',
+  '.servicenowservices.com',
+] as const
+
+/**
+ * Validates a ServiceNow instance URL to prevent SSRF attacks.
+ *
+ * ServiceNow instances are SaaS endpoints hosted on ServiceNow-owned domains.
+ * Example valid formats:
+ * - https://acme.service-now.com (standard commercial instances)
+ * - https://acme.servicenow.com (newer commercial domain)
+ * - https://acme.servicenowservices.com (GovCloud/FedRAMP)
+ *
+ * This validator ensures the URL:
+ * - Is a valid HTTPS URL (reuses validateExternalUrl for IP/localhost/port checks)
+ * - Has a hostname ending in a trusted ServiceNow-owned domain suffix
+ *
+ * Note: Customers using the Custom URLs plugin to front their instance with a
+ * vanity CNAME (e.g. support.acme.com) will be rejected. Point the connector at
+ * the underlying `*.service-now.com` host instead.
+ *
+ * @param url - The instance URL to validate
+ * @param paramName - Name of the parameter for error messages
+ * @returns ValidationResult
+ *
+ * @example
+ * ```typescript
+ * const result = validateServiceNowInstanceUrl(instanceUrl)
+ * if (!result.isValid) {
+ *   throw new Error(result.error)
+ * }
+ * ```
+ */
+export function validateServiceNowInstanceUrl(
+  url: string | null | undefined,
+  paramName = 'instanceUrl'
+): ValidationResult {
+  const urlResult = validateExternalUrl(url, paramName)
+  if (!urlResult.isValid) return urlResult
+
+  const hostname = new URL(url as string).hostname.toLowerCase()
+  const isAllowedHost = SERVICENOW_ALLOWED_HOST_SUFFIXES.some(
+    (suffix) => hostname === suffix.slice(1) || hostname.endsWith(suffix)
+  )
+
+  if (!isAllowedHost) {
+    logger.warn('ServiceNow instance URL hostname not on allowlist', {
+      paramName,
+      hostname: hostname.substring(0, 100),
+    })
+    return {
+      isValid: false,
+      error: `${paramName} must be a ServiceNow-hosted domain (e.g., *.service-now.com, *.servicenow.com, or *.servicenowservices.com)`,
+    }
+  }
+
+  return { isValid: true, sanitized: url as string }
+}
+
+const WORKDAY_ALLOWED_HOST_SUFFIXES = ['.workday.com', '.myworkday.com'] as const
+
+/**
+ * Validates a Workday tenant URL to prevent SSRF attacks.
+ *
+ * Workday tenant URLs are SaaS endpoints hosted on Workday-owned domains.
+ * Example valid formats:
+ * - https://wd2-impl-services1.workday.com (implementation/sandbox tenants)
+ * - https://wd5-services1.workday.com (production)
+ * - https://wd5-services1.myworkday.com (production, customer-facing endpoint)
+ *
+ * This validator ensures the URL:
+ * - Is a valid HTTPS URL (reuses validateExternalUrl for IP/localhost/port checks)
+ * - Has a hostname ending in a trusted Workday-owned domain suffix
+ *
+ * @param url - The tenant URL to validate
+ * @param paramName - Name of the parameter for error messages
+ * @returns ValidationResult
+ *
+ * @example
+ * ```typescript
+ * const result = validateWorkdayTenantUrl(tenantUrl)
+ * if (!result.isValid) {
+ *   throw new Error(result.error)
+ * }
+ * ```
+ */
+export function validateWorkdayTenantUrl(
+  url: string | null | undefined,
+  paramName = 'tenantUrl'
+): ValidationResult {
+  const urlResult = validateExternalUrl(url, paramName)
+  if (!urlResult.isValid) return urlResult
+
+  const hostname = new URL(url as string).hostname.toLowerCase()
+  const isAllowedHost = WORKDAY_ALLOWED_HOST_SUFFIXES.some(
+    (suffix) => hostname === suffix.slice(1) || hostname.endsWith(suffix)
+  )
+
+  if (!isAllowedHost) {
+    logger.warn('Workday tenant URL hostname not on allowlist', {
+      paramName,
+      hostname: hostname.substring(0, 100),
+    })
+    return {
+      isValid: false,
+      error: `${paramName} must be a Workday-hosted domain (e.g., *.workday.com or *.myworkday.com)`,
+    }
+  }
+
+  return { isValid: true, sanitized: url as string }
+}
diff --git a/apps/sim/providers/azure-anthropic/index.ts b/apps/sim/providers/azure-anthropic/index.ts
index 710d1ba90e8..999dc0938f8 100644
--- a/apps/sim/providers/azure-anthropic/index.ts
+++ b/apps/sim/providers/azure-anthropic/index.ts
@@ -1,6 +1,7 @@
 import Anthropic from '@anthropic-ai/sdk'
 import { createLogger } from '@sim/logger'
 import { env } from '@/lib/core/config/env'
+import { validateUrlWithDNS } from '@/lib/core/security/input-validation.server'
 import type { StreamingExecution } from '@/executor/types'
 import { executeAnthropicProviderRequest } from '@/providers/anthropic/core'
 import { getProviderDefaultModel, getProviderModels } from '@/providers/models'
@@ -19,13 +20,25 @@ export const azureAnthropicProvider: ProviderConfig = {
   executeRequest: async (
     request: ProviderRequest
   ): Promise<ProviderResponse | StreamingExecution> => {
-    const azureEndpoint = request.azureEndpoint || env.AZURE_ANTHROPIC_ENDPOINT
+    const userProvidedEndpoint = request.azureEndpoint
+    const azureEndpoint = userProvidedEndpoint || env.AZURE_ANTHROPIC_ENDPOINT
     if (!azureEndpoint) {
       throw new Error(
         'Azure endpoint is required for Azure Anthropic. Please provide it via the azureEndpoint parameter or AZURE_ANTHROPIC_ENDPOINT environment variable.'
       )
     }
 
+    if (userProvidedEndpoint) {
+      const validation = await validateUrlWithDNS(userProvidedEndpoint, 'azureEndpoint')
+      if (!validation.isValid) {
+        logger.warn('Blocked SSRF attempt via azureEndpoint', {
+          endpoint: userProvidedEndpoint,
+          error: validation.error,
+        })
+        throw new Error(`Invalid Azure Anthropic endpoint: ${validation.error}`)
+      }
+    }
+
     const apiKey = request.apiKey
     if (!apiKey) {
       throw new Error('API key is required for Azure Anthropic.')
diff --git a/apps/sim/providers/azure-openai/index.ts b/apps/sim/providers/azure-openai/index.ts
index 0d8566be602..d60354c77af 100644
--- a/apps/sim/providers/azure-openai/index.ts
+++ b/apps/sim/providers/azure-openai/index.ts
@@ -11,6 +11,7 @@ import type {
 } from 'openai/resources/chat/completions'
 import type { ReasoningEffort } from 'openai/resources/shared'
 import { env } from '@/lib/core/config/env'
+import { validateUrlWithDNS } from '@/lib/core/security/input-validation.server'
 import type { StreamingExecution } from '@/executor/types'
 import { MAX_TOOL_ITERATIONS } from '@/providers'
 import {
@@ -616,7 +617,8 @@ export const azureOpenAIProvider: ProviderConfig = {
   executeRequest: async (
     request: ProviderRequest
   ): Promise<ProviderResponse | StreamingExecution> => {
-    const azureEndpoint = request.azureEndpoint || env.AZURE_OPENAI_ENDPOINT
+    const userProvidedEndpoint = request.azureEndpoint
+    const azureEndpoint = userProvidedEndpoint || env.AZURE_OPENAI_ENDPOINT
 
     if (!azureEndpoint) {
       throw new Error(
@@ -624,6 +626,17 @@ export const azureOpenAIProvider: ProviderConfig = {
       )
     }
 
+    if (userProvidedEndpoint) {
+      const validation = await validateUrlWithDNS(userProvidedEndpoint, 'azureEndpoint')
+      if (!validation.isValid) {
+        logger.warn('Blocked SSRF attempt via azureEndpoint', {
+          endpoint: userProvidedEndpoint,
+          error: validation.error,
+        })
+        throw new Error(`Invalid Azure OpenAI endpoint: ${validation.error}`)
+      }
+    }
+
     const apiKey = request.apiKey
     if (!apiKey) {
       throw new Error('API key is required for Azure OpenAI.')
diff --git a/apps/sim/tools/workday/soap.ts b/apps/sim/tools/workday/soap.ts
index a1f269008f8..aeba1391a6c 100644
--- a/apps/sim/tools/workday/soap.ts
+++ b/apps/sim/tools/workday/soap.ts
@@ -1,5 +1,6 @@
 import { createLogger } from '@sim/logger'
 import * as soap from 'soap'
+import { validateWorkdayTenantUrl } from '@/lib/core/security/input-validation'
 
 const logger = createLogger('WorkdaySoapClient')
 
@@ -128,14 +129,20 @@ export interface WorkdayClient extends soap.Client {
 /**
  * Builds the WSDL URL for a Workday SOAP service.
  * Pattern: {tenantUrl}/ccx/service/{tenant}/{serviceName}/{version}?wsdl
+ *
+ * @throws Error if tenantUrl is not a trusted Workday-hosted URL (SSRF guard)
  */
 export function buildWsdlUrl(
   tenantUrl: string,
   tenant: string,
   service: WorkdayServiceKey
 ): string {
+  const validation = validateWorkdayTenantUrl(tenantUrl)
+  if (!validation.isValid) {
+    throw new Error(validation.error ?? 'Invalid tenantUrl')
+  }
   const svc = WORKDAY_SERVICES[service]
-  const baseUrl = tenantUrl.replace(/\/$/, '')
+  const baseUrl = (validation.sanitized ?? tenantUrl).replace(/\/$/, '')
   return `${baseUrl}/ccx/service/${tenant}/${svc.name}/${svc.version}?wsdl`
 }