CVE-2026-91149
Cockpit: cockpit: denial of service via unbounded connection thread spawning
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.
Fixes and workarounds
Workaround
Restrict network access to the Cockpit listener (TCP port 9090) to trusted management networks or localhost only, using host firewall rules such as firewalld zones or iptables rules that limit which sources may reach port 9090. If remote access to the Cockpit web console is not required, disable the listener entirely with `systemctl disable --now cockpit.socket`. External connection-rate or concurrency limits in front of TCP port 9090, such as those enforced by a firewall or reverse proxy, further reduce exploitability. Lowering the service's task or file-descriptor ceilings can reduce the blast radius, but does not correct the missing concurrency bound in the cockpit-tls accept path; fixes are being pursued for the affected product streams.
Source: CNA: redhatAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| Red Hat Enterprise Linux 9 Red Hat cockpit
https://access.redhat.com/downloads/content/package-browser/ |
≥ 0:356.4-1.el9_8; < * (unaffected, rpm)
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 10 Red Hat cockpit
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 7 Red Hat cockpit
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat Enterprise Linux 8 Red Hat cockpit
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: affected |
CNA: redhat |
| Red Hat OpenShift Dev Spaces Red Hat devspaces/udi-base-rhel10
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unaffected |
CNA: redhat |
| Red Hat OpenShift Dev Spaces Red Hat devspaces/udi-base-rhel9
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unaffected |
CNA: redhat |
| Red Hat OpenShift Dev Spaces Red Hat devspaces/udi-rhel9
https://access.redhat.com/downloads/content/package-browser/ |
Range not reported
Other versions: unaffected |
CNA: redhat |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 3.1 / 7.5 high |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CNA: redhat |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://access.redhat.com/errata/RHSA-2026:94533CNA: redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2026-91149CNA: redhat · vdb-entry, x_refsource_REDHAT
- https://bugzilla.redhat.com/show_bug.cgi?id=2479422CNA: redhat · issue-tracking, x_refsource_REDHAT
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