CVE-2026-49329 Red Hat CVE debrief

Who should care

Defenders and security teams responsible for openshift/oauth-server deployments should assess exposure and prioritize patching or mitigation. They should also monitor for suspicious traffic patterns and ensure robust security configurations to mitigate potential risks. Additionally, they should review compensating controls for exposed systems and track exceptions and retest remediated assets.

Why it matters

CVE-2026-49329 is a high-severity vulnerability in openshift/oauth-server that could allow unauthenticated attackers to cause a denial of service. Defenders should prioritize patching, monitoring, and robust security configurations to mitigate potential risks.

• Potential denial of service due to excessive CPU consumption
• Possible impact on authentication mechanisms for cluster users

Technical summary

The openshift/oauth-server is vulnerable to a denial of service attack due to improper handling of the Accept-Language header. An unauthenticated attacker can send a crafted header to consume excessive CPU, potentially denying authentication to all cluster users. The vulnerability is caused by the upstream guard counting only '-' characters, while the internal BCP 47 scanner aliases '_' to '-' after the guard check. This allows an attacker to trigger quadratic-time parsing, consuming excessive CPU and denying authentication to all cluster users.

Defensive priority

Defenders should prioritize verifying and applying patches, monitoring for suspicious traffic, and ensuring robust security configurations.

Recommended defensive actions

• Verify and apply patches or updates to the openshift/oauth-server
• Monitor for suspicious traffic patterns that could indicate exploitation attempts
• Ensure robust security configurations and input validation for the Accept-Language header
• 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 NVD entry provide details on the vulnerability, including its CVSS score and potential impact. The openshift/oauth-server is vulnerable to a denial of service attack due to improper handling of the Accept-Language header. The vulnerability has a CVSS score of 7.5 and is considered high-severity. There are no known exploits or attacks in the wild, but defenders should prioritize patching and mitigation.

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.