CVE-2026-24047 @backstage/cli-common has a possible `resolveSafeChildPath` Symlink Chain Bypass
Attackers can bypass path validation via symlink chains to read or modify files outside allowed directories in Backstage backend components.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-24047?
CVE-2026-24047 is a medium-severity path traversal vulnerability in backstage, published on 21 Jan 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Backstage is an open framework for building developer portals, and @backstage/cli-common provides config loading functionality used by the backend and command line interface of Backstage. Prior to version 0.1.17, 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 via symlink chains (creating `link1 → link2 → /outside` where intermediate symlinks eventually resolve outside the allowed directory) and 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. This vulnerability is fixed in `@backstage/backend-plugin-api` version 0.1.17. Users should upgrade to this version or later. Some workarounds are available. Run Backstage in a containerized environment with limited filesystem access and/or restrict template creation to trusted users.
Which versions are affected by CVE-2026-24047?
2 open source packages ship an affected version, including @backstage/cli-common.
| Package | Affected | Fixed in |
|---|---|---|
@backstage/cli-common npm | All versions | 0.1.17 |
@backstage/cli-common npm | All versions | 0.1.17 |
How do I fix CVE-2026-24047?
Upgrade @backstage/cli-common to 0.1.17 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-24047 being exploited?
There is no known exploitation of CVE-2026-24047 in the wild and no public exploit code.
Sources
Also known as GHSA-2p49-45hj-7mc9.