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, 06:26 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 2026-10-26.
What to do
AI-suggested
1. Immediately upgrade Hydra to a version including the patch from commit dea1e16 or later to ensure proper input sanitization and output encoding. 2. Until patching is possible, avoid building untrusted or third-party packages that could contain malicious scripts. 3. Restrict access to the Hydra web interface to trusted users only, ideally via VPN or network segmentation, to reduce exposure. 4. Implement Content Security Policy (CSP) headers on the Hydra web interface to limit the execution of unauthorized scripts. 5. Monitor build logs and database entries for suspicious or unexpected script content. 6. Educate developers and CI users about the risk of visiting untrusted build pages and encourage use of updated browsers with XSS protections. 7. Review and harden CI pipeline security policies to include package vetting and code review before builds. 8. 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.