CVE-2026-91149 Red Hat CVE debrief

Who should care

System administrators and defenders responsible for Cockpit installations, especially in contexts where remote access is common, should assess exposure and consider mitigation strategies to prevent resource exhaustion.

Why it matters

Defenders should care about CVE-2026-91149 because it allows an unauthenticated remote attacker to cause a denial of service in Cockpit installations, potentially leading to resource exhaustion and service unavailability. System administrators and defenders responsible for Cockpit installations should assess exposure, especially in contexts where remote access is common, and consider mitigation strategies to prevent resource exhaustion.

• Denial of service to legitimate users
• Consumption of system resources such as memory and file descriptors
• Potential degradation or complete unavailability of the Cockpit service

Technical summary

The vulnerability allows an unauthenticated remote attacker to cause a denial of service by initiating numerous simultaneous connections to the cockpit-tls service, leading to an unbounded number of detached threads and consumption of system resources such as memory and file descriptors. This can lead to resource exhaustion and service unavailability, especially in contexts where remote access is common. Defenders should prioritize verifying exposure of Cockpit installations and assess the feasibility of limiting concurrent connections to mitigate resource exhaustion.

Defensive priority

Defenders should prioritize verifying exposure of Cockpit installations, especially in contexts where remote access is common, and assess the feasibility of limiting concurrent connections to mitigate resource exhaustion.

Recommended defensive actions

• Verify exposure of Cockpit installations, especially in contexts where remote access is common
• Assess the feasibility of limiting concurrent connections to mitigate resource exhaustion
• Monitor system resource utilization and Cockpit service availability
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed

Evidence notes

The CVE record and source item provide details on the vulnerability, its impact, and affected products. However, specific versions of the affected products and detailed remediation steps are not provided.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.