CVE-2026-91147 Red Hat CVE debrief

Who should care

Defenders responsible for configuring and maintaining `cockpit-ws` should assess exposure and prioritize verification and updates. Affected roles include those responsible for configuring and maintaining `cockpit-ws`, as well as security teams and vulnerability management teams. The impact is supported by the CVE record and source item. Remediation priority is medium, but verification of affected versions and updates is necessary. Defenders should care

Why it matters

Defenders should care about CVE-2026-91147 because it allows a remote, unauthenticated attacker to cause a Denial of Service (DoS) in `cockpit-ws`, potentially leading to service unavailability. Affected roles include those responsible for configuring and maintaining `cockpit-ws`. The impact is supported by the CVE record and source item. Remediation priority is medium, but verification of affected versions and updates is necessary.

• Potential Denial of Service (DoS) impact on `cockpit-ws`
• Need to verify and update `cockpit-ws` configurations
• Possible service unavailability due to improper URL-root handling

Technical summary

A remote, unauthenticated attacker can cause a Denial of Service (DoS) in `cockpit-ws` by sending a specially crafted request when the `WebService.UrlRoot` is configured and a request is made to the exact URL-root prefix without a trailing slash. This issue can lead to service unavailability and requires verification of affected versions and updates. The vulnerability is triggered by a specific request pattern, emphasizing the need for defenders to assess exposure and prioritize verification and updates. The CVE record and source item provide details on the vulnerability, but affected versions and remediation steps require verification from official sources.

Defensive priority

Defenders should prioritize verifying and updating `cockpit-ws` configurations to prevent exploitation.

Recommended defensive actions

• Verify `cockpit-ws` configurations for proper URL-root handling
• Update `cockpit-ws` to the latest version if available
• Monitor for suspicious requests to the URL-root prefix
• 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
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and source item provide details on the vulnerability, but affected versions and remediation steps require verification from official sources. Defenders should verify `cockpit-ws` configurations for proper URL-root handling and update to the latest version if available. The vulnerability allows a remote, unauthenticated attacker to cause a Denial of Service (DoS) in `cockpit-ws`, potentially leading to service unavailability. Affected roles include those responsible for configuring and maintaining `cockpit-ws`. The lack

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.