CVE-2026-106509highCWE-1336CWE-94

CVE-2026-106509: high-severity vulnerability in backstage

Backstage: Improper validation of MkDocs theme configuration in TechDocs

Published · Updated

21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 7.7epss 0.3%
exploitation probability
0.3%top 84% of all CVEs
observed exploitation
nono source reports it
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.
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L
Affected products
@backstage · plugin-techdocs-nodebackstage · backstage
Related CVEs — backstage

In the same product, most dangerous first.

CVE-2023-35926HIGHInsecure sandbox in Backstage Scaffolder pluginEPSS 1.9%CVE-2021-41151MEDIUMPath Traversal in @backstage/plugin-scaffolder-backendEPSS 1.3%CVE-2021-32662MEDIUMTechDocs mkdocs.yml path traversalEPSS 1.3%CVE-2021-32660MEDIUMTechDocs content sanitization bypassEPSS 1.3%CVE-2021-43783HIGHPath Traversal in @backstage/plugin-scaffolder-backendEPSS 1.2%CVE-2021-32661MEDIUMTechDocs object element script injectionEPSS 1.2%
References
https://github.com/backstage/backstage/commit/02cd7cdbb18b687446277b5602adaee7f1d53cbbhttps://github.com/backstage/backstage/commit/a900a9953c8f7ad3ba1906d1d257725a9996cc9dhttps://github.com/backstage/backstage/releases/tag/v1.50.5https://github.com/backstage/backstage/releases/tag/v1.54.6https://github.com/backstage/backstage/security/advisories/GHSA-8w7q-29mw-gf5c