diff --git a/pods/preview/src/__tests__/middleware.test.ts b/pods/preview/src/__tests__/middleware.test.ts
new file mode 100644
index 00000000000..e8687da2f18
--- /dev/null
+++ b/pods/preview/src/__tests__/middleware.test.ts
@@ -0,0 +1,140 @@
+//
+// Copyright © 2026 Hardcore Engineering Inc.
+//
+// Licensed under the Eclipse Public License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License. You may
+// obtain a copy of the License at https://www.eclipse.org/legal/epl-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import { type AccountUuid, systemAccountUuid, type WorkspaceUuid } from '@hcengineering/core'
+import { extractToken } from '@hcengineering/server-client'
+import { type Token } from '@hcengineering/server-token'
+import { type NextFunction, type Response } from 'express'
+
+import { HttpError } from '../error'
+import { type RequestWithAuth, withAuthorization, withBlob } from '../middleware'
+
+jest.mock('@hcengineering/server-client', () => ({
+  extractToken: jest.fn()
+}))
+
+const extractTokenMock = extractToken as jest.MockedFunction<typeof extractToken>
+
+const workspaceA = '00000000-0000-4000-8000-00000000000a' as WorkspaceUuid
+const workspaceB = '00000000-0000-4000-8000-00000000000b' as WorkspaceUuid
+const account = '00000000-0000-4000-8000-0000000000ac' as AccountUuid
+
+function makeToken (token: Partial<Token>): Token {
+  const result: Token = { account, workspace: workspaceA, extra: {} }
+  return { ...result, ...token }
+}
+
+function makeRequest (workspace: string, name: string, token?: Token): RequestWithAuth {
+  return { headers: {}, params: { workspace, name }, token } as unknown as RequestWithAuth
+}
+
+const res = {} as unknown as Response
+
+describe('withAuthorization', () => {
+  beforeEach(() => {
+    extractTokenMock.mockReset()
+  })
+
+  it('rejects requests without a token', () => {
+    extractTokenMock.mockReturnValue(undefined)
+    const next = jest.fn() as unknown as NextFunction
+
+    withAuthorization(makeRequest(workspaceA, 'blob'), res, next)
+
+    expect(next).toHaveBeenCalledWith(expect.objectContaining({ code: 401 }))
+  })
+
+  it('rejects guest and readonly tokens', () => {
+    for (const extra of [{ guest: 'true' }, { readonly: 'true' }]) {
+      extractTokenMock.mockReturnValue(makeToken({ extra }))
+      const next = jest.fn() as unknown as NextFunction
+
+      withAuthorization(makeRequest(workspaceA, 'blob'), res, next)
+
+      expect(next).toHaveBeenCalledWith(expect.objectContaining({ code: 401 }))
+    }
+  })
+
+  it('attaches a valid token to the request', () => {
+    const token = makeToken({})
+    extractTokenMock.mockReturnValue(token)
+    const req = makeRequest(workspaceA, 'blob')
+    const next = jest.fn() as unknown as NextFunction
+
+    withAuthorization(req, res, next)
+
+    expect(req.token).toBe(token)
+    expect(next).toHaveBeenCalledWith()
+  })
+})
+
+describe('withBlob', () => {
+  it('rejects a missing workspace', () => {
+    const next = jest.fn() as unknown as NextFunction
+    withBlob(makeRequest('', 'blob'), res, next)
+    expect(next).toHaveBeenCalledWith(expect.objectContaining({ code: 400 }))
+  })
+
+  it('accepts a non-uuid workspace id when the token matches it', () => {
+    const workspace = 'not-a-uuid'
+    const next = jest.fn() as unknown as NextFunction
+
+    withBlob(makeRequest(workspace, 'blob', makeToken({ workspace: workspace as WorkspaceUuid })), res, next)
+
+    expect(next).toHaveBeenCalledWith()
+  })
+
+  it('rejects a missing blob name', () => {
+    const next = jest.fn() as unknown as NextFunction
+    withBlob(makeRequest(workspaceA, ''), res, next)
+    expect(next).toHaveBeenCalledWith(expect.objectContaining({ code: 400 }))
+  })
+
+  it('rejects a token scoped to another workspace', () => {
+    const next = jest.fn() as unknown as NextFunction
+
+    withBlob(makeRequest(workspaceB, 'blob', makeToken({ workspace: workspaceA })), res, next)
+
+    expect(next).toHaveBeenCalledWith(expect.any(HttpError))
+    expect(next).toHaveBeenCalledWith(expect.objectContaining({ code: 401 }))
+  })
+
+  it('allows a token scoped to the requested workspace', () => {
+    const next = jest.fn() as unknown as NextFunction
+
+    withBlob(makeRequest(workspaceA, 'blob', makeToken({ workspace: workspaceA })), res, next)
+
+    expect(next).toHaveBeenCalledWith()
+  })
+
+  it('allows the system account and admins to access any workspace', () => {
+    for (const token of [
+      makeToken({ account: systemAccountUuid, workspace: workspaceA }),
+      makeToken({ workspace: workspaceA, extra: { admin: 'true' } })
+    ]) {
+      const next = jest.fn() as unknown as NextFunction
+      withBlob(makeRequest(workspaceB, 'blob', token), res, next)
+      expect(next).toHaveBeenCalledWith()
+    }
+  })
+
+  it('rejects requests with no token attached', () => {
+    const next = jest.fn() as unknown as NextFunction
+
+    withBlob(makeRequest(workspaceA, 'blob'), res, next)
+
+    expect(next).toHaveBeenCalledWith(expect.objectContaining({ code: 401 }))
+  })
+})
diff --git a/pods/preview/src/middleware.ts b/pods/preview/src/middleware.ts
index 0d8b0e01870..017a053a1c2 100644
--- a/pods/preview/src/middleware.ts
+++ b/pods/preview/src/middleware.ts
@@ -66,6 +66,40 @@ export const withAuthorization = (req: RequestWithAuth, res: Response, next: Nex
   }
 }
 
+/**
+ * Validates blob route params and ensures the caller's token grants access to
+ * the workspace taken from the URL. Must run after `withAuthorization`, which
+ * guarantees a token is present.
+ */
+export const withBlob = (req: RequestWithAuth, res: Response, next: NextFunction): void => {
+  try {
+    const workspace = req.params.workspace
+    const name = req.params.name
+
+    if (workspace === undefined || workspace === '') {
+      throw new HttpError(400, 'Missing workspace')
+    }
+    if (name === undefined || name === '') {
+      throw new HttpError(400, 'Missing blob name')
+    }
+
+    const token = req.token
+    if (token == null) {
+      throw new HttpError(401, 'Unauthorized')
+    }
+
+    const hasWorkspaceAccess =
+      (token.workspace as string) === workspace || token.account === systemAccountUuid || token.extra?.admin === 'true'
+    if (!hasWorkspaceAccess) {
+      throw new HttpError(401, 'Unauthorized')
+    }
+
+    next()
+  } catch (err: any) {
+    next(err)
+  }
+}
+
 export interface ErrorHandlerOptions {
   ctx: MeasureContext
 }
diff --git a/pods/preview/src/server.ts b/pods/preview/src/server.ts
index 18026a42f1f..32fa7d67f0a 100644
--- a/pods/preview/src/server.ts
+++ b/pods/preview/src/server.ts
@@ -29,7 +29,7 @@ import { pipeline } from 'stream/promises'
 
 import { createCache } from './cache'
 import { type Config } from './config'
-import { type RequestWithAuth, errorHandler, keepAlive } from './middleware'
+import { type RequestWithAuth, errorHandler, keepAlive, withAuthorization, withBlob } from './middleware'
 import { createPreviewService, ThumbnailParams } from './service'
 import { TemporaryDir } from './tempdir'
 
@@ -174,6 +174,8 @@ export async function createServer (ctx: MeasureContext, config: Config): Promis
 
   app.get(
     '/metadata/:workspace/:name',
+    withAuthorization,
+    withBlob,
     wrapRequest(ctx, 'getMetadata', async (ctx, req, res) => {
       const workspace = req.params.workspace as WorkspaceUuid
       const name = req.params.name
@@ -185,6 +187,8 @@ export async function createServer (ctx: MeasureContext, config: Config): Promis
 
   app.get(
     '/image/:transform/:workspace/:name',
+    withAuthorization,
+    withBlob,
     wrapRequest(ctx, 'getThumbnail', async (ctx, req, res) => {
       const workspace = req.params.workspace as WorkspaceUuid
       const name = req.params.name