CVE-2026-74515 Linux CVE debrief

Who should care

System administrators and security teams managing Linux environments, especially those using KVM on s390 architectures, should assess exposure and apply patches or mitigations as necessary.

Why it matters

This vulnerability in the Linux kernel's KVM implementation for s390 could allow for resource leaks if adapter interrupt forwarding is enabled multiple times. Defenders should prioritize patching and monitoring systems for potential exploitation attempts.

• Verify and apply patches to prevent potential resource leaks.
• Review system logs for exploitation attempts.
• Update affected Linux versions to prevent vulnerability exploitation.

Technical summary

The Linux kernel's KVM implementation for s390 did not properly handle adapter interrupt forwarding, allowing it to be enabled multiple times. This could lead to resource leaks. The issue has been fixed by rejecting any request to enable interrupt forwarding if it's already enabled for the zPCI device. The fix ensures that the KVM implementation correctly manages adapter interrupts, preventing potential resource leaks and ensuring the security and stability of Linux environments using KVM on s390 architectures. The vulnerability was addressed by modifying the KVM implementation to properly handle adapter interrupt forwarding, preventing multiple enables and potential resource leaks.

Defensive priority

Defenders should prioritize verifying and applying patches for this vulnerability, especially in environments using KVM on s390 architectures.

Recommended defensive actions

• Verify and apply patches for this vulnerability, especially in environments using KVM on s390 architectures.
• Review and update affected Linux versions to ensure they are not vulnerable.
• Monitor system logs for potential exploitation attempts.
• 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 associated source item provide details on the vulnerability, including its description and affected versions. However, specific details about exploitation or victim impact 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.