diff --git a/apps/sim/app/api/files/download/route.ts b/apps/sim/app/api/files/download/route.ts
index 33f1ce61146..62bdbfe6e6a 100644
--- a/apps/sim/app/api/files/download/route.ts
+++ b/apps/sim/app/api/files/download/route.ts
@@ -4,8 +4,8 @@ import { fileDownloadContract } from '@/lib/api/contracts/storage-transfer'
 import { getValidationErrorMessage, parseRequest } from '@/lib/api/server'
 import { checkSessionOrInternalAuth } from '@/lib/auth/hybrid'
 import { withRouteHandler } from '@/lib/core/utils/with-route-handler'
-import type { StorageContext } from '@/lib/uploads/config'
 import { hasCloudStorage } from '@/lib/uploads/core/storage-service'
+import { inferContextFromKey } from '@/lib/uploads/utils/file-utils'
 import { verifyFileAccess } from '@/app/api/files/authorization'
 import { createErrorResponse, FileNotFoundError } from '@/app/api/files/utils'
 
@@ -40,7 +40,7 @@ export const POST = withRouteHandler(async (request: NextRequest) => {
     )
     if (!parsed.success) return parsed.response
 
-    const { key, name, isExecutionFile, context, url } = parsed.data.body
+    const { key, name, url } = parsed.data.body
 
     if (!key) {
       return createErrorResponse(new Error('File key is required'), 400)
@@ -58,12 +58,9 @@ export const POST = withRouteHandler(async (request: NextRequest) => {
       })
     }
 
-    let storageContext: StorageContext | 'general' | undefined = context
-
-    if (isExecutionFile && !context) {
-      storageContext = 'execution'
-      logger.info(`Using execution context for file: ${key}`)
-    }
+    // Derive context from the trusted key prefix, mirroring the serve route this URL
+    // delegates to, which re-derives context from the key and ignores any client-supplied value.
+    const storageContext = inferContextFromKey(key)
 
     const hasAccess = await verifyFileAccess(
       key,
@@ -79,10 +76,9 @@ export const POST = withRouteHandler(async (request: NextRequest) => {
     }
 
     const { getBaseUrl } = await import('@/lib/core/utils/urls')
-    const contextQuery = storageContext ? `?context=${storageContext}` : ''
-    const downloadUrl = `${getBaseUrl()}/api/files/serve/${encodeURIComponent(key)}${contextQuery}`
+    const downloadUrl = `${getBaseUrl()}/api/files/serve/${encodeURIComponent(key)}?context=${storageContext}`
 
-    logger.info(`Generated download URL for ${storageContext ?? 'inferred'} file: ${key}`)
+    logger.info(`Generated download URL for ${storageContext} file: ${key}`)
 
     return NextResponse.json({
       downloadUrl,
diff --git a/apps/sim/app/api/files/parse/route.ts b/apps/sim/app/api/files/parse/route.ts
index b925a366033..033f180818a 100644
--- a/apps/sim/app/api/files/parse/route.ts
+++ b/apps/sim/app/api/files/parse/route.ts
@@ -13,7 +13,7 @@ import { checkInternalAuth } from '@/lib/auth/hybrid'
 import { sanitizeUrlForLog } from '@/lib/core/utils/logging'
 import { assertKnownSizeWithinLimit, isPayloadSizeLimitError } from '@/lib/core/utils/stream-limits'
 import { isSupportedFileType, parseFile } from '@/lib/file-parsers'
-import { isUsingCloudStorage, type StorageContext, StorageService } from '@/lib/uploads'
+import { isUsingCloudStorage, StorageService } from '@/lib/uploads'
 import { uploadExecutionFile } from '@/lib/uploads/contexts/execution'
 import {
   ExternalUrlValidationError,
@@ -303,7 +303,6 @@ async function parseFileSingle(
     return handleCloudFile(
       filePath,
       fileType,
-      undefined,
       userId,
       executionContext,
       maxDownloadBytes,
@@ -329,7 +328,6 @@ async function parseFileSingle(
     return handleCloudFile(
       filePath,
       fileType,
-      undefined,
       userId,
       executionContext,
       maxDownloadBytes,
@@ -608,7 +606,6 @@ async function handleExternalUrl(
 async function handleCloudFile(
   filePath: string,
   fileType: string,
-  explicitContext: string | undefined,
   userId: string,
   executionContext?: ExecutionContext,
   maxDownloadBytes = MAX_DOWNLOAD_SIZE_BYTES,
@@ -619,7 +616,7 @@ async function handleCloudFile(
 
     logger.info('Extracted cloud key:', cloudKey)
 
-    const context = (explicitContext as StorageContext) || inferContextFromKey(cloudKey)
+    const context = inferContextFromKey(cloudKey)
 
     const hasAccess = await verifyFileAccess(
       cloudKey,
@@ -658,7 +655,7 @@ async function handleCloudFile(
       maxBytes: maxDownloadBytes,
     })
     logger.info(
-      `Downloaded file from ${context} storage (${explicitContext ? 'explicit' : 'inferred'}): ${cloudKey}, size: ${fileBuffer.length} bytes`
+      `Downloaded file from ${context} storage: ${cloudKey}, size: ${fileBuffer.length} bytes`
     )
 
     const filename = originalFilename || cloudKey.split('/').pop() || cloudKey
diff --git a/apps/sim/lib/uploads/utils/file-utils.server.test.ts b/apps/sim/lib/uploads/utils/file-utils.server.test.ts
new file mode 100644
index 00000000000..40e9ec97044
--- /dev/null
+++ b/apps/sim/lib/uploads/utils/file-utils.server.test.ts
@@ -0,0 +1,47 @@
+/**
+ * @vitest-environment node
+ */
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+const { mockDownloadFile } = vi.hoisted(() => ({
+  mockDownloadFile: vi.fn(),
+}))
+
+vi.mock('@/lib/uploads/core/storage-service', () => ({
+  downloadFile: mockDownloadFile,
+  hasCloudStorage: vi.fn(() => true),
+}))
+
+vi.mock('@/app/api/files/authorization', () => ({
+  verifyFileAccess: vi.fn(),
+}))
+
+import { createLogger } from '@sim/logger'
+import { downloadFileFromStorage } from '@/lib/uploads/utils/file-utils.server'
+import type { UserFile } from '@/executor/types'
+
+describe('downloadFileFromStorage context derivation', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+    mockDownloadFile.mockResolvedValue(Buffer.from('bytes'))
+  })
+
+  it('downloads with the key-derived context, ignoring a caller-supplied public context', async () => {
+    const userFile: UserFile = {
+      id: 'f1',
+      name: 'report.pdf',
+      url: '',
+      size: 5,
+      type: 'application/pdf',
+      key: 'workspace/ws-1/1700000000000-abc1234-report.pdf',
+      context: 'og-images',
+    }
+
+    await downloadFileFromStorage(userFile, 'req-1', createLogger('test'))
+
+    expect(mockDownloadFile).toHaveBeenCalledTimes(1)
+    expect(mockDownloadFile).toHaveBeenCalledWith(
+      expect.objectContaining({ key: userFile.key, context: 'workspace' })
+    )
+  })
+})
diff --git a/apps/sim/lib/uploads/utils/file-utils.server.ts b/apps/sim/lib/uploads/utils/file-utils.server.ts
index e495b94274a..1077512cc97 100644
--- a/apps/sim/lib/uploads/utils/file-utils.server.ts
+++ b/apps/sim/lib/uploads/utils/file-utils.server.ts
@@ -12,7 +12,6 @@ import {
   consumeOrCancelBody,
   readResponseToBufferWithLimit,
 } from '@/lib/core/utils/stream-limits'
-import type { StorageContext } from '@/lib/uploads'
 import { StorageService } from '@/lib/uploads'
 import { isExecutionFile } from '@/lib/uploads/contexts/execution/utils'
 import {
@@ -23,6 +22,7 @@ import {
   isInternalFileUrl,
   processSingleFileToUserFile,
   type RawFileInput,
+  resolveTrustedFileContext,
 } from '@/lib/uploads/utils/file-utils'
 import { verifyFileAccess } from '@/app/api/files/authorization'
 import type { UserFile } from '@/executor/types'
@@ -90,7 +90,7 @@ export async function resolveFileInputToUrl(
 
     // Generate presigned URL if we have a key but no URL
     if (!fileUrl && userFile.key) {
-      const context = (userFile.context as StorageContext) || inferContextFromKey(userFile.key)
+      const context = resolveTrustedFileContext(userFile.key, userFile.context)
       const hasAccess = await verifyFileAccess(userFile.key, userId, undefined, context, false)
 
       if (!hasAccess) {
@@ -281,10 +281,8 @@ export async function downloadFileFromStorage(
     )
     buffer = await downloadExecutionFile(userFile, { maxBytes: options.maxBytes })
   } else if (userFile.key) {
-    const context = (userFile.context as StorageContext) || inferContextFromKey(userFile.key)
-    logger.info(
-      `[${requestId}] Downloading from ${context} storage (${userFile.context ? 'explicit' : 'inferred'}): ${userFile.key}`
-    )
+    const context = resolveTrustedFileContext(userFile.key, userFile.context)
+    logger.info(`[${requestId}] Downloading from ${context} storage: ${userFile.key}`)
 
     const { downloadFile } = await import('@/lib/uploads/core/storage-service')
     buffer = await downloadFile({
diff --git a/apps/sim/lib/uploads/utils/file-utils.test.ts b/apps/sim/lib/uploads/utils/file-utils.test.ts
index d982f33e2a4..0e7581bb454 100644
--- a/apps/sim/lib/uploads/utils/file-utils.test.ts
+++ b/apps/sim/lib/uploads/utils/file-utils.test.ts
@@ -9,6 +9,7 @@ import {
   isInternalFileUrl,
   isNetworkError,
   processSingleFileToUserFile,
+  resolveTrustedFileContext,
 } from '@/lib/uploads/utils/file-utils'
 
 const logger = createLogger('FileUtilsTest')
@@ -74,6 +75,26 @@ describe('inferContextFromKey', () => {
   })
 })
 
+describe('resolveTrustedFileContext', () => {
+  it('derives from the key prefix and ignores a mismatched caller context', () => {
+    expect(resolveTrustedFileContext('workspace/ws/1700000000000-abc-x.pdf', 'og-images')).toBe(
+      'workspace'
+    )
+    expect(resolveTrustedFileContext('chat/x', 'workspace-logos')).toBe('chat')
+    expect(resolveTrustedFileContext('workspace/ws/x', 'mothership')).toBe('workspace')
+  })
+
+  it('honors the caller context for legacy keys with no inferrable prefix', () => {
+    expect(resolveTrustedFileContext('legacy/ws/wf/ex/report.pdf', 'execution')).toBe('execution')
+  })
+
+  it('never resolves an un-inferrable key to a world-readable context', () => {
+    expect(() => resolveTrustedFileContext('legacy/report.pdf', 'og-images')).toThrow()
+    expect(() => resolveTrustedFileContext('legacy/report.pdf', 'profile-pictures')).toThrow()
+    expect(() => resolveTrustedFileContext('legacy/report.pdf')).toThrow()
+  })
+})
+
 describe('isAbortError', () => {
   it('returns true for AbortError-named errors', () => {
     const err = new Error('aborted')
diff --git a/apps/sim/lib/uploads/utils/file-utils.ts b/apps/sim/lib/uploads/utils/file-utils.ts
index 0fd254f2e25..642e48aafd2 100644
--- a/apps/sim/lib/uploads/utils/file-utils.ts
+++ b/apps/sim/lib/uploads/utils/file-utils.ts
@@ -596,6 +596,43 @@ export function inferContextFromKey(key: string): StorageContext {
   )
 }
 
+/**
+ * World-readable storage contexts. Reads for these short-circuit file
+ * authorization and can resolve to the shared bucket, so a caller-supplied
+ * context must never select one for a key that does not carry the matching
+ * prefix.
+ */
+const PUBLIC_STORAGE_CONTEXTS = new Set<StorageContext>([
+  'profile-pictures',
+  'og-images',
+  'workspace-logos',
+])
+
+/**
+ * Resolve the storage context for a stored file from its trusted key prefix.
+ *
+ * The storage key is written server-side at upload time and cannot be forged to
+ * change tenant, whereas a file's `context` field is attacker-authorable in a
+ * workflow. When the key carries a recognized prefix that prefix is
+ * authoritative and the caller-supplied `context` is ignored — this prevents a
+ * private `workspace/…` key from being relabeled with a world-readable context
+ * to bypass authorization and read the shared bucket.
+ *
+ * Legacy keys predating context-prefixed keys cannot be inferred; for those the
+ * persisted `context` is honored so existing files stay resolvable — except a
+ * world-readable context, which would reopen the bypass on an un-inferrable key.
+ */
+export function resolveTrustedFileContext(key: string, context?: string): StorageContext {
+  try {
+    return inferContextFromKey(key)
+  } catch (error) {
+    if (context && !PUBLIC_STORAGE_CONTEXTS.has(context as StorageContext)) {
+      return context as StorageContext
+    }
+    throw error
+  }
+}
+
 /**
  * Extract storage key and context from an internal file URL
  * @param fileUrl - Internal file URL (e.g., /api/files/serve/key?context=workspace)
diff --git a/apps/sim/providers/file-attachments.server.ts b/apps/sim/providers/file-attachments.server.ts
index 8f2e2dfac5e..4ca03ef07aa 100644
--- a/apps/sim/providers/file-attachments.server.ts
+++ b/apps/sim/providers/file-attachments.server.ts
@@ -2,9 +2,8 @@ import { FileState, GoogleGenAI } from '@google/genai'
 import { createLogger } from '@sim/logger'
 import { getErrorMessage } from '@sim/utils/errors'
 import { sleep } from '@sim/utils/helpers'
-import type { StorageContext } from '@/lib/uploads'
 import { StorageService } from '@/lib/uploads'
-import { inferContextFromKey } from '@/lib/uploads/utils/file-utils'
+import { resolveTrustedFileContext } from '@/lib/uploads/utils/file-utils'
 import { downloadServableFileFromStorage } from '@/lib/uploads/utils/file-utils.server'
 import { verifyFileAccess } from '@/app/api/files/authorization'
 import type { UserFile } from '@/executor/types'
@@ -85,7 +84,7 @@ export async function attachLargeFileRemoteUrls(
       )
     }
 
-    const context = (file.context as StorageContext) || inferContextFromKey(file.key)
+    const context = resolveTrustedFileContext(file.key, file.context)
     const hasAccess = await verifyFileAccess(file.key, request.userId, undefined, context, false)
     if (!hasAccess) {
       throw new Error(`File "${file.name}" is not accessible for provider "${providerId}"`)
@@ -147,7 +146,7 @@ async function assertFileAccessForUpload(
   if (!userId) {
     throw new Error(`File "${file.name}" requires an authenticated user to upload`)
   }
-  const context = (file.context as StorageContext) || inferContextFromKey(file.key)
+  const context = resolveTrustedFileContext(file.key, file.context)
   const hasAccess = await verifyFileAccess(file.key, userId, undefined, context, false)
   if (!hasAccess) {
     throw new Error(`File "${file.name}" is not accessible`)