CVE-2026-55251: NetBox Device Type Library arbitrary code execution in CI workflow

CVE-2026-55251 · Severity: medium · CVSS 6.5 · Published 2026-10-01

NetBox Device Type Library is a community-managed collection of device type definitions used by the NetBox infrastructure management system. An untrusted contributor could submit a pull request that modifies configuration files (requirements.txt, pre-commit configs, or .gitmodules) to inject malicious code that executes on GitHub's CI runner before any maintainer review. While the runner has limited privileges and no access to repository secrets, an attacker could potentially exfiltrate the read-only GITHUB_TOKEN or disrupt the CI pipeline.

Technologies: NetBox Community Device Type Library. Vendors: NetBox Community.

Quick answers

Is CVE-2026-55251 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-55251 being exploited in the wild.
How severe is CVE-2026-55251?
Medium severity, with a CVSS score of 6.5, published 1 October 2026.
Which products and versions are affected?
netbox-community Device Type Library.
Is there a fix for CVE-2026-55251?
Yes: fixed in commit f41fc1e48dec8d7d31afba5f13a8c73652ff5796. Until then: Implement a gating validate-inputs job in the CI workflow that blocks PR code execution unless the contributor has write permission, is Dependabot, or a maintainer has approved the PR with a label. Restrict PR-editable files to contribution directories only (device-types/, module-types/, rack-types/, elevation-images/, module-images/). Enforce CODEOWNERS review on CI control files (/.github/). Set least-privilege token permissions (contents: read) at the workflow level. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-55251 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-55251?
Check whether you run NetBox Community Device Type Library. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • Fixed in: commit f41fc1e48dec8d7d31afba5f13a8c73652ff5796

Implement a gating validate-inputs job in the CI workflow that blocks PR code execution unless the contributor has write permission, is Dependabot, or a maintainer has approved the PR with a label. Restrict PR-editable files to contribution directories only (device-types/, module-types/, rack-types/, elevation-images/, module-images/). Enforce CODEOWNERS review on CI control files (/.github/). Set least-privilege token permissions (contents: read) at the workflow level.

Technical details

The vulnerability stems from a pull-request-triggered CI workflow that executes code from untrusted contributors before maintainer review. Three files are exploitable: requirements.txt (pip install executes arbitrary setup.py), .pre-commit-hooks-config.yaml/.pre-commit-yamlfmt-config.yaml (pre-commit clones and runs hook repositories), and .gitmodules (actions/checkout fetches submodule URLs). An unauthenticated attacker can open a PR modifying these files to achieve RCE on the CI runner. The impact is limited to read-only token theft and runner resource abuse, as fork PRs receive a read-only GITHUB_TOKEN with no repository secret access, though the inherited risk of pull_request workflows remains.

Affected products

  • netbox-community Device Type Library

Timeline

  • 2026-10-01: disclosed
  • 2026-06-11: patched: commit f41fc1e (published in advisory; predates public disclosure)

References

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