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

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

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Aug 2025
- **Updated:** 12 Aug 2025
- **Also known as:** GHSA-qpq3-646c-vgx9

## 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 (Missing Authentication for Critical Functionality)

## Which versions are affected by CVE-2025-54864?

It affects 1 product.


Products: 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.

## Is CVE-2025-54864 being exploited?

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

## Other vulnerabilities in NixOS hydra

- [CVE-2024-45049](https://insights.sbomify.com/CVE-2024-45049/): Nix Hydra Missing authentication when triggering evaluations (high 7.5)
- [CVE-2025-54800](https://insights.sbomify.com/CVE-2025-54800/): Hydra persistent XSS in build metrics (high 7.1)
- [CVE-2024-32657](https://insights.sbomify.com/CVE-2024-32657/): Hydra has persistent XSS vulnerability serving HTML build outputs (medium 4.6)
- [CVE-2025-32435](https://insights.sbomify.com/CVE-2025-32435/): Hydra no restricted eval after nix-eval-jobs migration (low 2.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-54864 and fix it if it is affected.

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

Affected product: NixOS hydra. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2025-54864/ (Markdown: https://insights.sbomify.com/CVE-2025-54864/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-54864
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-54864
- OSV: https://osv.dev/vulnerability/CVE-2025-54864

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-54864/
Summaries are generated and may contain mistakes; the official description above is the record.