# 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.

- **Severity:** High 7.4 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 26 Jun 2026
- **Updated:** 27 Jun 2026
- **Also known as:** GHSA-jj36-r9w3-3pfh

## 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 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2026-50136?

2 open source packages ship an affected version, including @budibase/server. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `@budibase/server` | npm | All versions | 3.39.2 |
| `@budibase/server` | npm | All versions | 3.39.2 |

Products: Budibase Budibase.

## How do I fix CVE-2026-50136?

Upgrade @budibase/server to 3.39.2 or later.

## 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](https://insights.sbomify.com/CVE-2026-54350/): Budibase: Anonymous NoSQL operator injection via published-app query templates (critical 10.0)
- [CVE-2026-27702](https://insights.sbomify.com/CVE-2026-27702/): Budibase Vulnerable to Remote Code Execution via Unsafe eval() in View Filter Map Function (Budibase Cloud) (critical 9.9)
- [CVE-2026-54352](https://insights.sbomify.com/CVE-2026-54352/): Budibase: Arbitrary file read by workspace-builder via PWA-zip symlink upload (critical 9.6)
- [CVE-2026-31818](https://insights.sbomify.com/CVE-2026-31818/): Budibase: Server-Side Request Forgery via REST Connector with Empty Default Blacklist (critical 9.6)
- [CVE-2026-30240](https://insights.sbomify.com/CVE-2026-30240/): Budibase PWA ZIP Upload Path Traversal Allows Reading Arbitrary Server Files Including All Environment Secrets (critical 9.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-50136 and fix it if it is affected.

What it is: 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.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-50136 exists.

Affected packages and fixed versions:
- @budibase/server (npm): affected all versions; fixed in 3.39.2
- @budibase/server (npm): affected all versions; fixed in 3.39.2

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-50136/ (Markdown: https://insights.sbomify.com/CVE-2026-50136/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-50136
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-50136
- OSV: https://osv.dev/vulnerability/CVE-2026-50136

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-50136/
Summaries are generated and may contain mistakes; the official description above is the record.