CVE-2026-42298 Postiz: Arbitrary Code Execution and Token Exfiltration in pr-docker-build.yml via untrusted Dockerfile.dev

Critical 10.0 Published 8 May 2026 Updated 11 May 2026

Attackers can execute arbitrary code and steal privileged tokens by submitting a malicious Pull Request with a modified Dockerfile in the Postiz repository.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-42298?

CVE-2026-42298 is a critical code injection vulnerability in gitroomhq postiz-app, published on 8 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Postiz is an AI social media scheduling tool. Prior to commit da44801, a "Pwn Request" vulnerability in the Build and Publish PR Docker Image workflow (.github/workflows/pr-docker-build.yml) allows any unauthenticated user to execute arbitrary code during the Docker build process and exfiltrate a highly privileged GITHUB_TOKEN (write-all permissions). This can be achieved simply by opening a Pull Request from a fork with a maliciously modified Dockerfile.dev. This issue has been patched via commit da44801.

Weakness: CWE-94

Which versions are affected by CVE-2026-42298?

It affects 1 product.

Products include Gitroom Postiz.

How do I fix CVE-2026-42298?

No fix has been published for CVE-2026-42298 yet. Limit exposure of the affected software until one is available.

Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.

Is CVE-2026-42298 being exploited?

There is no known exploitation of CVE-2026-42298 in the wild and no public exploit code.

Public exploit code: 1 proofs of concept on GitHub.

Sources

Also known as GHSA-v975-9h5p-xhm4.