# CVE-2025-54800: Hydra persistent XSS in build metrics

> A malicious package can inject JavaScript into Hydra build pages, allowing attackers to execute code in visitors' browsers.

- **Severity:** High 7.1 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 12 Aug 2025
- **Updated:** 12 Aug 2025
- **Also known as:** GHSA-7qwg-q53v-vh99

## What is CVE-2025-54800?

CVE-2025-54800 is a high-severity cross-site scripting vulnerability in NixOS hydra, published on 12 Aug 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

Hydra is a continuous integration service for Nix based projects. Prior to commit dea1e16, a malicious package can introduce arbitrary JavaScript code into the Hydra database that is automatically evaluated in a client's browser when anyone visits the build page. This could be done by a third-party project as part of its build process. This also happens in other places like with hydra-release-name. This issue has been patched by commit dea1e16. A workaround involves either not building untrusted packages or not visiting the builds page.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2025-54800?

It affects 1 product.


Products: Nixos Hydra.

## How do I fix CVE-2025-54800?

No fix has been published for CVE-2025-54800 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-54800 being exploited?

There is no known exploitation of CVE-2025-54800 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-2025-54864](https://insights.sbomify.com/CVE-2025-54864/): Hydra missing authentication when triggering evaluations through GitHub and Gitea plugins (medium 6.9)
- [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-2025-54800 and fix it if it is affected.

What it is: CVE-2025-54800 is a high-severity cross-site scripting vulnerability in NixOS hydra, published on 12 Aug 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2025-54800 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-2025-54800/ (Markdown: https://insights.sbomify.com/CVE-2025-54800/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-54800
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-54800
- OSV: https://osv.dev/vulnerability/CVE-2025-54800

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From sbomify Insights: https://insights.sbomify.com/CVE-2025-54800/
Summaries are generated and may contain mistakes; the official description above is the record.