CVE-2026-29186 @backstage/plugin-techdocs-node: TechDocs Mkdocs Configuration Key Enables Arbitrary Code Execution
Attackers can execute arbitrary Python code by crafting a malicious mkdocs.yml file, bypassing security controls in the Backstage TechDocs plugin.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-29186?
CVE-2026-29186 is a high-severity code injection vulnerability in backstage, published on 7 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-29186?
2 open source packages ship an affected version, including @backstage/plugin-techdocs-node. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
@backstage/plugin-techdocs-node npm | All versions | 1.14.3 |
@backstage/plugin-techdocs-node npm | All versions | 1.14.3 |
Products include Linuxfoundation Backstage Plugin-Techdocs-Node.
How do I fix CVE-2026-29186?
Upgrade @backstage/plugin-techdocs-node to 1.14.3 or later.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-29186 being exploited?
There is no known exploitation of CVE-2026-29186 in the wild and no public exploit code.
Sources
Also known as GHSA-928r-fm4v-mvrw.