simstudioai · TheodoreSpeaks · Aug 15, 2026 · Aug 15, 2026
diff --git a/apps/sim/blocks/blocks/credential-group.ts b/apps/sim/blocks/blocks/credential-group.ts
@@ -21,14 +21,13 @@ const CREDENTIAL_GROUP_CANONICAL_GROUP = {
   advancedIds: ['manualCredentialGroup'],
 } as const satisfies CanonicalGroup
 
-async function fetchCachedCredentialGroups(signal?: AbortSignal) {
+async function fetchCachedCredentialGroups() {
   const workspaceId = useWorkflowRegistry.getState().hydration.workspaceId
   if (!workspaceId) return []
 
   return getQueryClient().fetchQuery({
     queryKey: credentialGroupKeys.list(workspaceId),
-    queryFn: ({ signal: querySignal }) =>
-      fetchCredentialGroupList(workspaceId, signal ?? querySignal),
+    queryFn: ({ signal }) => fetchCredentialGroupList(workspaceId, signal),
     staleTime: CREDENTIAL_GROUP_LIST_STALE_TIME,
   })
 }
@@ -170,8 +169,8 @@ export const CredentialGroupBlock: BlockConfig<CredentialGroupBlockOutput> = {
           .map((group) => ({ label: group.name, id: group.id }))
           .sort((a, b) => a.label.localeCompare(b.label))
       },
-      fetchOptionById: async (_blockId: string, optionId: string, signal?: AbortSignal) => {
-        const groups = await fetchCachedCredentialGroups(signal)
+      fetchOptionById: async (_blockId: string, optionId: string) => {
+        const groups = await fetchCachedCredentialGroups()
         const group = groups.find((candidate) => candidate.id === optionId)
         return group ? { label: group.name, id: group.id } : null
       },
@@ -220,10 +219,10 @@ export const CredentialGroupBlock: BlockConfig<CredentialGroupBlockOutput> = {
           })
           .sort((a, b) => a.label.localeCompare(b.label))
       },
-      fetchOptionById: async (blockId: string, optionId: string, signal?: AbortSignal) => {
+      fetchOptionById: async (blockId: string, optionId: string) => {
         const credentialGroupId = resolveCredentialGroupIdForBlock(blockId)
         if (!credentialGroupId) return null
-        const groups = await fetchCachedCredentialGroups(signal)
+        const groups = await fetchCachedCredentialGroups()
         const group = groups.find((candidate) => candidate.id === credentialGroupId)
         const option = group?.options.find(
           (candidate) =>

diff --git a/apps/sim/lib/api/contracts/credential-groups.ts b/apps/sim/lib/api/contracts/credential-groups.ts
@@ -5,6 +5,7 @@ import {
   CREDENTIAL_GROUP_PROVIDER_IDS,
   CREDENTIAL_GROUP_STANDARD_OAUTH_PROVIDER_IDS,
 } from '@/lib/credential-groups/providers'
+import { CREDENTIAL_GROUP_ENROLLMENT_CURSOR_MAX_LENGTH } from '@/lib/credential-groups/types'
 
 export const credentialGroupProviderSchema = z.enum(CREDENTIAL_GROUP_PROVIDER_IDS)
 export const credentialGroupStatusSchema = z.enum(['active', 'disabled'])
@@ -169,7 +170,11 @@ export const slackCredentialGroupConfigurationCallbackQuerySchema =
   credentialGroupOAuthCallbackQuerySchema
 
 export const credentialGroupEnrollmentListQuerySchema = z.object({
-  cursor: z.string().min(1, 'Enrollment cursor cannot be empty').max(128).optional(),
+  cursor: z
+    .string()
+    .min(1, 'Enrollment cursor cannot be empty')
+    .max(CREDENTIAL_GROUP_ENROLLMENT_CURSOR_MAX_LENGTH)
+    .optional(),
   limit: z.coerce.number().int().min(1).max(100).default(50),
 })
 

diff --git a/apps/sim/lib/credential-groups/enrollments.test.ts b/apps/sim/lib/credential-groups/enrollments.test.ts
@@ -4,6 +4,7 @@
 import { dbChainMockFns, queueTableRows, resetDbChainMock, schemaMock } from '@sim/testing'
 import { inArray } from 'drizzle-orm'
 import { beforeEach, describe, expect, it, vi } from 'vitest'
+import { credentialGroupEnrollmentListQuerySchema } from '@/lib/api/contracts/credential-groups'
 
 const { adapter } = vi.hoisted(() => ({
   adapter: {
@@ -151,6 +152,9 @@ describe('listCredentialGroupEnrollments', () => {
       statuses: ['invited', 'in_progress', 'completed', 'delivery_failed'],
     })
     if (!firstPage.nextCursor) throw new Error('Expected a next enrollment cursor')
+    expect(
+      credentialGroupEnrollmentListQuerySchema.parse({ cursor: firstPage.nextCursor }).cursor
+    ).toBe(firstPage.nextCursor)
     const result = await listCredentialGroupEnrollments(
       'workspace-1',
       'group-1',
@@ -171,6 +175,70 @@ describe('listCredentialGroupEnrollments', () => {
     ])
   })
 
+  it('rejects a cursor replayed against another credential group or filter', async () => {
+    const remainingEnrollment = {
+      ...ENROLLMENT,
+      id: 'enrollment-2',
+      invitedAt: new Date('2026-08-10T12:00:00.000Z'),
+    }
+    dbChainMockFns.limit
+      .mockResolvedValueOnce([{ options: [] }])
+      .mockResolvedValueOnce([{ enrollment: ENROLLMENT }, { enrollment: remainingEnrollment }])
+      .mockResolvedValueOnce([{ options: [] }])
+      .mockResolvedValueOnce([{ options: [] }])
+
+    const filters = { statuses: ['invited' as const, 'completed' as const] }
+    const firstPage = await listCredentialGroupEnrollments(
+      'workspace-1',
+      'group-1',
+      1,
+      undefined,
+      filters
+    )
+    if (!firstPage.nextCursor) throw new Error('Expected a next enrollment cursor')
+
+    await expect(
+      listCredentialGroupEnrollments('workspace-1', 'group-2', 50, firstPage.nextCursor, filters)
+    ).rejects.toMatchObject({ message: 'Enrollment cursor is invalid', status: 400 })
+    await expect(
+      listCredentialGroupEnrollments('workspace-1', 'group-1', 50, firstPage.nextCursor, {
+        statuses: ['completed'],
+      })
+    ).rejects.toMatchObject({ message: 'Enrollment cursor is invalid', status: 400 })
+  })
+
+  it('rejects a cursor whose signed boundary was modified', async () => {
+    const remainingEnrollment = {
+      ...ENROLLMENT,
+      id: 'enrollment-2',
+      invitedAt: new Date('2026-08-10T12:00:00.000Z'),
+    }
+    dbChainMockFns.limit
+      .mockResolvedValueOnce([{ options: [] }])
+      .mockResolvedValueOnce([{ enrollment: ENROLLMENT }, { enrollment: remainingEnrollment }])
+      .mockResolvedValueOnce([{ options: [] }])
+
+    const firstPage = await listCredentialGroupEnrollments('workspace-1', 'group-1', 1)
+    if (!firstPage.nextCursor) throw new Error('Expected a next enrollment cursor')
+    const [encoded, signature] = firstPage.nextCursor.split('.')
+    if (!encoded || !signature) throw new Error('Expected a signed enrollment cursor')
+    const payload = JSON.parse(Buffer.from(encoded, 'base64url').toString('utf8')) as Record<
+      string,
+      unknown
+    >
+    payload.id = 'fabricated-boundary'
+    const modifiedEncoded = Buffer.from(JSON.stringify(payload), 'utf8').toString('base64url')
+
+    await expect(
+      listCredentialGroupEnrollments(
+        'workspace-1',
+        'group-1',
+        50,
+        `${modifiedEncoded}.${signature}`
+      )
+    ).rejects.toMatchObject({ message: 'Enrollment cursor is invalid', status: 400 })
+  })
+
   it('rejects a malformed enrollment cursor', async () => {
     dbChainMockFns.limit.mockResolvedValueOnce([{ options: [] }])
 

diff --git a/apps/sim/lib/credential-groups/enrollments.ts b/apps/sim/lib/credential-groups/enrollments.ts
@@ -7,14 +7,17 @@ import {
   user,
   workspace,
 } from '@sim/db/schema'
+import { safeCompare } from '@sim/security/compare'
 import { sha256Hex } from '@sim/security/hash'
+import { hmacSha256Hex } from '@sim/security/hmac'
 import { getErrorMessage } from '@sim/utils/errors'
 import { generateId } from '@sim/utils/id'
 import { normalizeEmail, truncate } from '@sim/utils/string'
 import { and, count, desc, eq, inArray, lt, or, sql } from 'drizzle-orm'
 import { renderCredentialGroupInvitationEmail } from '@/components/emails/credential-groups/render'
 import { getCredentialGroupInvitationSubject } from '@/components/emails/subjects'
 import { getWorkspaceOwnerSubscriptionAccess } from '@/lib/billing/core/workspace-access'
+import { env } from '@/lib/core/config/env'
 import { getBaseUrl } from '@/lib/core/utils/urls'
 import { isCredentialGroupsAvailable } from '@/lib/credential-groups/availability'
 import { getCredentialGroupProviderAdapter } from '@/lib/credential-groups/provider-registry'
@@ -134,26 +137,41 @@ export class CredentialGroupEnrollmentError extends Error {
 }
 
 interface CredentialGroupEnrollmentCursor {
+  v: 1
   id: string
   invitedAt: Date
 }
 
 function encodeCredentialGroupEnrollmentCursor(
-  enrollment: Pick<EnrollmentRow, 'id' | 'invitedAt'>
+  enrollment: Pick<EnrollmentRow, 'id' | 'invitedAt'>,
+  scope: string
 ): string {
-  return Buffer.from(
-    JSON.stringify({ id: enrollment.id, invitedAt: enrollment.invitedAt.toISOString() })
+  const encoded = Buffer.from(
+    JSON.stringify({ v: 1, id: enrollment.id, invitedAt: enrollment.invitedAt.toISOString() })
   ).toString('base64url')
+  return `${encoded}.${hmacSha256Hex(`${encoded}.${scope}`, env.BETTER_AUTH_SECRET)}`
 }
 
-function decodeCredentialGroupEnrollmentCursor(cursor: string): CredentialGroupEnrollmentCursor {
+function decodeCredentialGroupEnrollmentCursor(
+  cursor: string,
+  scope: string
+): CredentialGroupEnrollmentCursor {
   try {
-    const decoded: unknown = JSON.parse(Buffer.from(cursor, 'base64url').toString('utf8'))
+    const [encoded, signature, extra] = cursor.split('.')
+    if (!encoded || !signature || extra !== undefined) {
+      throw new Error('Cursor token is malformed')
+    }
+    const expectedSignature = hmacSha256Hex(`${encoded}.${scope}`, env.BETTER_AUTH_SECRET)
+    if (!safeCompare(signature, expectedSignature)) {
+      throw new Error('Cursor signature is invalid')
+    }
+    const decoded: unknown = JSON.parse(Buffer.from(encoded, 'base64url').toString('utf8'))
     if (!decoded || typeof decoded !== 'object' || Array.isArray(decoded)) {
       throw new Error('Cursor payload must be an object')
     }
-    const { id, invitedAt: invitedAtValue } = decoded as Record<string, unknown>
+    const { v, id, invitedAt: invitedAtValue } = decoded as Record<string, unknown>
     if (
+      v !== 1 ||
       typeof id !== 'string' ||
       !id.trim() ||
       id !== id.trim() ||
@@ -166,12 +184,27 @@ function decodeCredentialGroupEnrollmentCursor(cursor: string): CredentialGroupE
     if (Number.isNaN(invitedAt.getTime()) || invitedAt.toISOString() !== invitedAtValue) {
       throw new Error('Cursor timestamp is invalid')
     }
-    return { id, invitedAt }
+    return { v, id, invitedAt }
   } catch {
     throw new CredentialGroupEnrollmentError('Enrollment cursor is invalid', 400)
   }
 }
 
+function credentialGroupEnrollmentCursorScope(
+  workspaceId: string,
+  groupId: string,
+  filters: ListCredentialGroupEnrollmentFilters
+): string {
+  return sha256Hex(
+    JSON.stringify({
+      workspaceId,
+      groupId,
+      email: filters.email || null,
+      statuses: [...new Set(filters.statuses ?? [])].sort(),
+    })
+  )
+}
+
 function hashInvitationToken(token: string): string {
   return sha256Hex(token)
 }
@@ -482,7 +515,10 @@ export async function listCredentialGroupEnrollments(
     .filter((option) => option.status === 'active')
     .map((option) => option.id)
 
-  const cursorPosition = cursor ? decodeCredentialGroupEnrollmentCursor(cursor) : undefined
+  const cursorScope = credentialGroupEnrollmentCursorScope(workspaceId, groupId, filters)
+  const cursorPosition = cursor
+    ? decodeCredentialGroupEnrollmentCursor(cursor, cursorScope)
+    : undefined
 
   const rows = await db
     .select({ enrollment: credentialGroupEnrollment })
@@ -564,7 +600,7 @@ export async function listCredentialGroupEnrollments(
       connections: connectionsByEnrollment.get(enrollment.id) ?? [],
     })),
     nextCursor: nextCursorEnrollment
-      ? encodeCredentialGroupEnrollmentCursor(nextCursorEnrollment)
+      ? encodeCredentialGroupEnrollmentCursor(nextCursorEnrollment, cursorScope)
       : null,
   }
 }

diff --git a/apps/sim/lib/credential-groups/types.ts b/apps/sim/lib/credential-groups/types.ts
@@ -1,5 +1,7 @@
 import type { CredentialGroupProvider } from '@/lib/credential-groups/providers'
 
+export const CREDENTIAL_GROUP_ENROLLMENT_CURSOR_MAX_LENGTH = 256
+
 interface CredentialGroupOptionInputBase {
   label: string
   required: boolean