CVE-2026-38991 Cockpit Vulnerable to Unrestricted Upload of File with Dangerous Type
An authenticated attacker can bypass file extension filters to upload PHP files, enabling arbitrary code execution on the server.
- 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-2026-38991?
CVE-2026-38991 is a high-severity vulnerability in n/a, published on 29 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Cockpit 2.13.5 and earlier is affected by a misconfiguration within the Bucket component _isFileTypeAllowed function where a specially crafted filename bypasses an extension filter. This allows an authenticated attacker to rename arbitrary files with the .php file extension enabling arbitrary code to be executed on the underlying server.
Weakness: CWE-434
Which versions are affected by CVE-2026-38991?
2 open source packages ship an affected version, including cockpit-hq/cockpit.
| Package | Affected | Fixed in |
|---|---|---|
cockpit-hq/cockpit Packagist | All versions | 2.14.0 |
cockpit-hq/cockpit Packagist | All versions | 2.14.0 |
How do I fix CVE-2026-38991?
Upgrade cockpit-hq/cockpit to 2.14.0 or later.
Is CVE-2026-38991 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-38991 exists.
Sources
Also known as GHSA-j2rx-4jg9-79mw.