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.
A flaw was found in Backstage. 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 file that causes arbitrary Python code execution.
To mitigate this issue, enable docker isolation by updating the Backstage configuration to use 'runIn: docker' instead of 'runIn: local', confining the arbitrary Python code execution to a containerized environment. Additionally, limit commit access to repositories tracked by Backstage to trusted contributors only, and enforce mandatory pull request (PR) reviews for any modifications made to the mkdocs.yml file.