CVE-2026-106509: backstage Code Injection

Vulnerability summary

CVE-2026-106509 is a high (CVSS 8.8) Code Injection vulnerability in backstage. EPSS estimates a 0.37% chance of exploitation in the next 30 days, higher than 29.3% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 06-10-2026
   PublishedVulnerability first disclosed.
2. 07-10-2026
   Last modifiedVulnerability information updated.

Description

Backstage is an open framework for building developer portals. Prior to 1.14.6, the @backstage/plugin-techdocs-node package is affected by improper validation of mkdocs theme configuration in techdocs. When TechDocs is configured to build documentation locally or in a container, a user with write access to a registered repository can include configuration values in mkdocs.yml that cause arbitrary code execution during the documentation build process. This issue is fixed in versions 1.14.6 and 1.15.4.

• CWE-94Improper Control of Generation of Code ('Code Injection')The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
• CWE-1336Improper Neutralization of Special Elements Used in a Template EngineThe product uses a template engine to insert or process externally-influenced input, but it does not neutralize or incorrectly neutralizes special elements or syntax that can be interpreted as template expressions or other code directives when processed by the engine.