CVE-2025-54800: NixOS hydra · Cross-site Scripting
Affects NixOS hydraSource CVE Database V5
Not known to be exploited · CVSS 7.1 High.
Data as of 26 Oct 2026, 10:12 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:H/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 12 Aug 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
AI-suggested
- Immediately upgrade Hydra to a version including the patch from commit dea1e16 or later to ensure proper input sanitization and output encoding.
- Until patching is possible, avoid building untrusted or third-party packages that could contain malicious scripts.
- Restrict access to the Hydra web interface to trusted users only, ideally via VPN or network segmentation, to reduce exposure.
- Implement Content Security Policy (CSP) headers on the Hydra web interface to limit the execution of unauthorized scripts.
- Monitor build logs and database entries for suspicious or unexpected script content.
- Educate developers and CI users about the risk of visiting untrusted build pages and encourage use of updated browsers with XSS protections.
- Review and harden CI pipeline security policies to include package vetting and code review before builds.
- Consider deploying web application firewalls (WAFs) that can detect and block XSS payloads targeting Hydra interfaces.
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.