Vulnerability record · CVE-2026-25153 · published 30 January 2026
CVE-2026-25153: Linuxfoundation backstage code injection vulnerability
Linuxfoundation · Backstage
Backstage is an open framework for building developer portals, and @backstage/plugin-techdocs-node provides common node.js functionalities for TechDocs. In versions of @backstage/plugin-techdocs-node prior to 1.13.11 and 1.14.1, when TechDocs is configured with `runIn: local`, a malicious actor who can submit or modify a repository's `mkdocs.yml` file can execute arbitrary Python code on the TechDocs build server via MkDocs hooks configuration. @backstage/plugin-techdocs-node versions 1.13.11 and 1.14.1 contain a fix. The fix introduces an allowlist of supported MkDocs configuration keys. Unsupported configuration keys (including `hooks`) are now removed from `mkdocs.yml` before running the generator, with a warning logged to indicate which keys were removed. Users of `@techdocs/cli` should also upgrade to the latest version, which includes the fixed `@backstage/plugin-techdocs-node` dependency. Some workarounds are available. Configure TechDocs with `runIn: docker` instead of `runIn: local` to provide container isolation, though it does not fully mitigate the risk. Limit who can modify `mkdocs.yml` files in repositories that TechDocs processes; only allow trusted contributors. Implement PR review requirements for changes to `mkdocs.yml` files to detect malicious `hooks` configurations before they are merged. Use MkDocs < 1.4.0 (e.g., 1.3.1) which does not support hooks. Note: This may limit access to newer MkDocs features. Building documentation in CI/CD pipelines using `@techdocs/cli` does not mitigate this vulnerability, as the CLI uses the same vulnerable `@backstage/plugin-techdocs-node` package.
Description
Backstage is an open framework for building developer portals, and @backstage/plugin-techdocs-node provides common node.js functionalities for TechDocs. In versions of @backstage/plugin-techdocs-node prior to 1.13.11 and 1.14.1, when TechDocs is configured with `runIn: local`, a malicious actor who can submit or modify a repository's `mkdocs.yml` file can execute arbitrary Python code on the TechDocs build server via MkDocs hooks configuration. @backstage/plugin-techdocs-node versions 1.13.11 and 1.14.1 contain a fix. The fix introduces an allowlist of supported MkDocs configuration keys. Unsupported configuration keys (including `hooks`) are now removed from `mkdocs.yml` before running the generator, with a warning logged to indicate which keys were removed. Users of `@techdocs/cli` should also upgrade to the latest version, which includes the fixed `@backstage/plugin-techdocs-node` dependency. Some workarounds are available. Configure TechDocs with `runIn: docker` instead of `runIn: local` to provide container isolation, though it does not fully mitigate the risk. Limit who can modify `mkdocs.yml` files in repositories that TechDocs processes; only allow trusted contributors. Implement PR review requirements for changes to `mkdocs.yml` files to detect malicious `hooks` configurations before they are merged. Use MkDocs < 1.4.0 (e.g., 1.3.1) which does not support hooks. Note: This may limit access to newer MkDocs features. Building documentation in CI/CD pipelines using `@techdocs/cli` does not mitigate this vulnerability, as the CLI uses the same vulnerable `@backstage/plugin-techdocs-node` package.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Affected products
1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.
References
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Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2026-25153), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.
