GHSA-928r-fm4v-mvrw

Source

https://github.com/advisories/GHSA-928r-fm4v-mvrw

Import Source

https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-928r-fm4v-mvrw/GHSA-928r-fm4v-mvrw.json

JSON Data

https://api.osv.dev/v1/vulns/GHSA-928r-fm4v-mvrw

Aliases

CVE-2026-29186

Published

2026-03-05T00:12:07Z

Modified

2026-03-09T16:02:26.288095Z

Severity

7.7 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L CVSS Calculator

Summary

TechDocs Mkdocs Configuration Key Enables Arbitrary Code Execution

Details

Impact

This is a configuration bypass vulnerability that enables arbitrary code execution. The @backstage/plugin-techdocs-node package uses an allowlist to filter dangerous MkDocs configuration keys during the documentation build process.

A gap in this allowlist allows attackers to craft an mkdocs.yml that causes arbitrary Python code execution, completely bypassing TechDocs' security controls.

Patches

Patched in @backstage/plugin-techdocs-node version 1.14.3

Workarounds

If users cannot upgrade immediately:

Use Docker mode with restricted access: Configure TechDocs with runIn: docker instead of runIn: local. This provides container isolation, though it does not fully mitigate the risk.
Restrict repository access: Limit who can modify mkdocs.yml files in repositories that TechDocs processes. Only allow trusted contributors.
Manual review: Implement PR review requirements for changes to mkdocs.yml files to detect malicious hooks configurations before they are merged.
Downgrade MkDocs: Use MkDocs < 1.4.0 (e.g., 1.3.1) which does not support hooks. Note: This may limit access to newer MkDocs features.

Note: Building documentation in CI/CD pipelines using @techdocs/cli does not mitigate this vulnerability, as the CLI uses the same vulnerable @backstage/plugin-techdocs-node package.

Resources

MkDocs Hooks Documentation MkDocs 1.4 Release Notes TechDocs Architecture

Database specific

{
    "cwe_ids": [
        "CWE-434",
        "CWE-74"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-05T00:12:07Z",
    "nvd_published_at": "2026-03-07T15:15:55Z",
    "severity": "HIGH"
}

References

Affected packages

npm / @backstage/plugin-techdocs-node

Package

Name: @backstage/plugin-techdocs-node; View open source insights on deps.dev
Purl: pkg:npm/%40backstage/plugin-techdocs-node

Affected ranges

Type: SEMVER
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

1.14.3

Database specific

source

"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/03/GHSA-928r-fm4v-mvrw/GHSA-928r-fm4v-mvrw.json"

last_known_affected_version_range

"<= 1.14.2"