CVE-2026-80602 Linux CVE debrief

Who should care

Defenders and security teams responsible for Linux kernel environments, especially those handling sensitive data or with high security requirements, should assess exposure and prioritize mitigation.

Why it matters

CVE-2026-80602 is a Linux kernel vulnerability that exposes kernel addresses to user space through the perf subsystem, potentially leading to information disclosure and increased risk of targeted attacks.

• Kernel address exposure can lead to potential information disclosure
• Increased risk of targeted attacks or exploitation
• Potential impact on system security and data confidentiality
• Requires verification of Linux kernel versions and configurations

Technical summary

The Linux kernel vulnerability CVE-2026-80602 allows kernel addresses to be exposed to user space through the perf subsystem. This occurs because the hardware filter only considers the privilege level of the branch target, not the branch source. As a result, user-only branch stacks can contain kernel-originating branches, leaking kernel addresses. The vulnerability affects Linux kernel environments where perf is used, especially in systems handling sensitive data or with high security requirements. Defenders should prioritize verifying and mitigating this vulnerability.

Defensive priority

Defenders should prioritize verifying and mitigating this vulnerability in Linux kernel environments where perf is used, especially in systems handling sensitive data or with high security requirements.

Recommended defensive actions

• Verify Linux kernel versions and configurations to ensure they are not vulnerable
• Implement software filtering to validate branch-from addresses against br_sel
• Monitor perf subsystem usage and kernel address exposure
• Review and update Linux kernel configurations to prevent similar vulnerabilities
• 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

Evidence notes

The CVE record and associated references provide details on the vulnerability, including its description, affected components, and potential impact. However, specific exploitation details or affected versions are not provided, requiring further verification.

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.