CVE-2026-29186
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedBackstage 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe @backstage/plugin-techdocs-node package has an incomplete allowlist for filtering dangerous MkDocs configuration keys during documentation builds. Attackers can craft malicious mkdocs.yml files that execute arbitrary Python code, completely bypassing TechDocs security controls. This affects all Backstage instances using TechDocs prior to version 1.14.3.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 1.14.3CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
-
Identify installed version of @backstage/plugin-techdocs-nodeRun 'npm list @backstage/plugin-techdocs-node' in your Backstage project root, or check your package.json dependencies for the installed version numberAffected if The installed version is lower than 1.14.3 (e.g., 1.14.0, 1.13.0, etc.)
-
Verify TechDocs plugin is in useCheck if TechDocs is configured in your Backstage app-config.yaml under the 'techdocs:' section, or if the techdocs-backend plugin is registered in your backend/index.tsAffected if TechDocs is enabled and processes mkdocs.yml files for documentation builds
-
Confirm documentation source handlingInspect your TechDocs configuration to determine if mkdocs.yml files come from external sources (e.g., external repositories, user-submitted content) that could contain malicious configurationAffected if Your documentation builds process mkdocs.yml files from sources outside your direct control
You are affected if @backstage/plugin-techdocs-node is installed at a version lower than 1.14.3 AND your Backstage instance uses TechDocs to build documentation from mkdocs.yml files, particularly from external or untrusted sources.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped1.14.3
Upgrade @backstage/plugin-techdocs-node to version 1.14.3 or later to apply the patched allowlist that blocks dangerous configuration keys and prevents arbitrary code execution.
1.14.3
- Identify the current version of @backstage/plugin-techdocs-node in your project by checking package.json or package-lock.json
- Update the package to version 1.14.3 or later using your package manager (e.g., npm install @backstage/plugin-techdocs-node@^1.14.3 or yarn add @backstage/plugin-techdocs-node@^1.14.3)
- Run npm install or yarn install to update the dependency
- Verify the upgrade was successful by checking the installed version
- Test that your TechDocs functionality works correctly after the upgrade
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation1.0 h
- Testing4.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,176.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-29186 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-29186 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data