Backstage up to 1.14.5/1.15.3 @backstage/plugin-techdocs-node mkdocs.yml code injection

Summaryinfo

A vulnerability classified as critical has been found in Backstage up to 1.14.5/1.15.3. This impacts an unknown function of the file mkdocs.yml of the component @backstage/plugin-techdocs-node. Performing a manipulation results in code injection. This vulnerability is cataloged as CVE-2026-106509. It is possible to initiate the attack remotely. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in Backstage up to 1.14.5/1.15.3. This affects some unknown processing of the file mkdocs.yml of the component @backstage/plugin-techdocs-node. The manipulation with an unknown input leads to a code injection vulnerability. CWE is classifying the issue as CWE-94. 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. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-106509 since 10/06/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1059 according to MITRE ATT&CK.

Upgrading to version 1.14.6 or 1.15.4 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-94074). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Name

• Backstage

Version

• 1.14.0
• 1.14.1
• 1.14.2
• 1.14.3
• 1.14.4
• 1.14.5
• 1.15.0
• 1.15.1
• 1.15.2
• 1.15.3

Website

• Product: https://github.com/backstage/backstage/

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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