CVE-2025-54864 Hydra missing authentication when triggering evaluations through GitHub and Gitea plugins

Medium 6.9 Published 12 Aug 2025 Updated 12 Aug 2025

Attackers can trigger resource-intensive evaluations without authentication, causing denial of service on the Hydra CI host.

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-2025-54864?

CVE-2025-54864 is a medium-severity missing authorization vulnerability in NixOS hydra, published on 12 Aug 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Hydra is a continuous integration service for Nix based projects. Prior to commit f7bda02, /api/push-github and /api/push-gitea are called by the corresponding forge without HTTP Basic authentication. Both forges do however feature HMAC signing with a secret key. Triggering an evaluation can be very taxing on the infrastructure when large evaluations are done, introducing potential denial of service attacks on the host running the evaluator. This issue has been patched by commit f7bda02. A workaround involves blocking /api/push-github and /api/push-gitea via a reverse proxy.

Weakness: CWE-306

Which versions are affected by CVE-2025-54864?

It affects 1 product.

Products include Nixos Hydra.

How do I fix CVE-2025-54864?

No fix has been published for CVE-2025-54864 yet. Limit exposure of the affected software until one is available.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2025-54864 being exploited?

There is no known exploitation of CVE-2025-54864 in the wild and no public exploit code.

Sources

Also known as GHSA-qpq3-646c-vgx9.