GHSA-6x9p-4r67-5gjx Budibase authenticated arbitrary S3 signed upload URL issuance via `/api/attachments/:datasourceId/url`

• npm @budibase/server: <= 3.38.1 (no fix yet)

Summary Budibase 3.39.7 allows a low-privilege authenticated published-app user with the built-in BASIC role to obtain arbitrary S3 pre-signed upload URLs backed by a workspace datasource's stored server-side credentials. The affected endpoint is: `POST /api/attachments/:datasourceId/url` The caller can control: ```text bucket key ``` and receives: ```text signedUrl publicUrl ``` This lets a low-privilege published-app user mint S3 `PUT` URLs using server-side datasource credentials for attacker-chosen object destinations. Steps: 1. Log in as an admin user. 2. Create a new app/workspace. 3. In the development app context, create an S3 datasource with valid credentials. 4. Publish the app. 5. Create a low-privilege user with the built-in BASIC role on the published production app ID. 6. Log in as that BASIC user. 7. Send: `POST /api/attachments//url` with: ```json {"bucket":"foo","key":"bar"} ``` and the published app header: ```text x-budibase-app-id: ``` Observe a successful response containing: ```text signedUrl publicUrl ``` Observed result The following behavior: dev BASIC request: 403 User does not have permission app publish: SUCCESS prod BASIC request: 200 OK Example confirmed runtime values from the final successful run: ```text prodAppId: app_e6b4cdc6cd6949969a83ff11eee88c5a datasourceId: datasource_0cec491b26a742468257c62382aa3284 publicUrl: https://foo.s3.eu-west-1.amazonaws.com/bar ``` The returned signedUrl contained standard AWS signing markers, including: ```text X-Amz-Credential=bb X-Amz-Signature X-Amz-Expires=900 ``` Impact A low-privilege published-app user who knows a valid datasource ID can mint S3 upload URLs backed by server-side datasource credentials and choose arbitrary destination bucket and key values. Route definition `packages/server/src/api/routes/static.ts:45` Authorization logic `packages/server/src/middleware/authorized.ts` `packages/server/src/middleware/resourceId.ts` Controller logic `packages/server/src/api/controllers/static/index.ts` Datasource lookup `packages/server/src/sdk/workspace/datasources/datasources.ts`