CVE-2026-50136 Budibase: Unauthenticated S3 signed upload URL generation allows arbitrary writes with stored datasource credentials
Unauthenticated users can generate S3 presigned URLs to write arbitrary files using stored datasource credentials, bypassing authentication and permission checks.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-50136?
CVE-2026-50136 is a high-severity missing authorization vulnerability in budibase, published on 26 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Budibase is an open-source low-code platform. Prior to 3.39.3, the application server exposes an unauthenticated endpoint that generates S3 PutObject presigned URLs using credentials stored in a workspace datasource. The route is protected only by the recaptcha middleware and does not require authentication, table permission, datasource permission, or builder access. A public caller who knows a workspace ID and S3 datasource ID can request a signed upload URL for attacker-controlled bucket and key values. This vulnerability is fixed in 3.39.3.
Weakness: CWE-306
Which versions are affected by CVE-2026-50136?
2 open source packages ship an affected version, including @budibase/server. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
@budibase/server npm | All versions | 3.39.2 |
@budibase/server npm | All versions | 3.39.2 |
Products include Budibase Budibase.
How do I fix CVE-2026-50136?
Upgrade @budibase/server to 3.39.2 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-50136 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-50136 exists.
Other vulnerabilities in budibase
- CVE-2026-54350 Budibase: Anonymous NoSQL operator injection via published-app query templates
- CVE-2026-27702 Budibase Vulnerable to Remote Code Execution via Unsafe eval() in View Filter Map Function (Budibase Cloud)
- CVE-2026-54352 Budibase: Arbitrary file read by workspace-builder via PWA-zip symlink upload
- CVE-2026-31818 Budibase: Server-Side Request Forgery via REST Connector with Empty Default Blacklist
- CVE-2026-30240 Budibase PWA ZIP Upload Path Traversal Allows Reading Arbitrary Server Files Including All Environment Secrets
Sources
Also known as GHSA-jj36-r9w3-3pfh.