CVE-2026-57856 Cockpit CMS Path Traversal via Bucket Name in Bucket File Storage API
Authenticated low-privileged users can traverse directories to list, upload, and delete files across all buckets in Cockpit CMS.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-57856?
CVE-2026-57856 is a high-severity path traversal vulnerability in Cockpit CMS, published on 13 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Cockpit CMS contains a path traversal vulnerability in the Bucket file storage API (/system/buckets/api). The api() method in modules/System/Controller/Buckets.php sanitizes the bucket name with preg_replace('/[^a-zA-Z0-9-_\\.]/','', $bucket), which permits '..' and '../' sequences. The sanitized value is interpolated into a Flysystem path as uploads://buckets/{bucket}. Flysystem's WhitespacePathNormalizer resolves 'buckets/..' to the empty string (the uploads storage root) without raising PathTraversalDetected because the '..' has a preceding component to consume. An authenticated low-privileged user can send a crafted request with a '../' bucket name to list, upload, and delete files across all buckets, including those belonging to other users or roles
Weakness: CWE-22
Which versions are affected by CVE-2026-57856?
How do I fix CVE-2026-57856?
No fix has been published for CVE-2026-57856 yet. Limit exposure of the affected software until one is available.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-57856 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-57856 exists.
Sources
Also known as GHSA-cfx5-q5qm-x936.