CVE-2026-24047

Description

### Impact The `resolveSafeChildPath` utility function in `@backstage/backend-plugin-api`, which is used to prevent path traversal attacks, failed to properly validate symlink chains and dangling symlinks. An attacker could bypass the path validation by: 1. **Symlink chains**: Creating `link1 → link2 → /outside` where intermediate symlinks eventually resolve outside the allowed directory 2. **Dangling symlinks**: Creating symlinks pointing to non-existent paths outside the base directory, which would later be created during file operations This function is used by Scaffolder actions and other backend components to ensure file operations stay within designated directories. ### Patches This vulnerability is fixed in `@backstage/backend-plugin-api` version 0.1.17. Users should upgrade to this version or later. ### Workarounds - Run Backstage in a containerised environment with limited filesystem access - Restrict template creation to trusted users

How to fix CVE-2026-24047

To remediate CVE-2026-24047, upgrade the affected package to a fixed version below.

• —upgrade to 0.1.17 or later

Is CVE-2026-24047 being exploited?

Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.

Affected packages (1)

• from 0, < 0.1.17

CVSS scores

References (4)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2026-24047
• PATCHgithub.com/backstage/backstage
• WEBgithub.com/backstage/backstage/commit/ae4dd5d1572a4f639e1a466fd982656b50f8e692
• WEBgithub.com/backstage/backstage/security/advisories/GHSA-2p49-45hj-7mc9