Описание
@backstage/cli-common has a possible resolveSafeChildPath Symlink Chain Bypass
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:
- Symlink chains: Creating
link1 → link2 → /outsidewhere intermediate symlinks eventually resolve outside the allowed directory - 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
Пакеты
@backstage/cli-common
<= 0.1.16
0.1.17
Связанные уязвимости
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 l