CVE-2026-91149 Cockpit: cockpit: denial of service via unbounded connection thread spawning
Unauthenticated attackers can cause denial of service in Cockpit by opening numerous simultaneous connections, exhausting system resources.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-91149?
CVE-2026-91149 is a high-severity denial of service vulnerability in Red Hat Enterprise Linux 10, published on 18 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A flaw was found in Cockpit. An unauthenticated remote attacker can exploit this vulnerability by initiating and sustaining numerous simultaneous connections to the `cockpit-tls` service. This forces the service to create an unbounded number of detached threads, consuming system resources such as memory and file descriptors. The primary consequence is a denial of service (DoS), leading to degradation or complete unavailability of the Cockpit service for legitimate users.
Weakness: CWE-770
Which versions are affected by CVE-2026-91149?
How do I fix CVE-2026-91149?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-91149 being exploited?
There is no known exploitation of CVE-2026-91149 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-91149, GHSA-3m8q-36jp-wgm3, UBUNTU-CVE-2026-91149.