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Fencer Intel
medium 6.5

CVE-2026-55251 json

NetBox Device Type Library: Arbitrary Code Execution on CI Runner Through Malicious requirements.txt, .pre-commit-hooks-config.yaml, and .gitmodules Files

published 5mo ago modified last mo. also EUVD-2026-91045 , GHSA-5x2m-x42f-g4cm

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository netbox-community/devicetype-library. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits
0
none known

Summary

NetBox Device Type Library is a collection of community-sourced device type definitions for import into NetBox. Prior to commit f41fc1e, the CI workflow .github/workflows/validation.yml runs on pull_request and executes code supplied by the pull request before any maintainer review. Three PR-editable files drive this: "requirements.txt", ".pre-commit-hooks-config.yaml" / ".pre-commit-yamlfmt-config.yaml", and ".gitmodules". A contributor with no special repository access could open a pull request that modifies these files and have their code run on the CI runner. This issue has been patched via commit f41fc1e.

Patch / fix

Is CVE-2026-55251 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.13% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/netbox-community/devicetype-library/security/advisories/GHSA-5x2m-x42f-g4cm referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected products

  • netbox-community devicetype-library

Classification

Weakness
  • CWE-94 Improper Control of Generation of Code
  • CWE-494 Download of Code Without Integrity Check
  • CWE-829 Inclusion of Functionality from Untrusted Control Sphere

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of netbox-community/devicetype-library published their own advisory on GitHub. Reviewed sources take precedence over it.