CVE-2026-98413 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, SELinux users and administrators, and security teams responsible for Linux systems should be aware of this vulnerability. They should review and apply the patch to ensure proper SELinux functionality and verify AVC decision handling to prevent potential issues. Additionally, operators of Linux systems using SELinux should be aware of the potential impact and take steps to verify and apply the patch as necessary.

Why it matters

A vulnerability in the Linux kernel's SELinux implementation has been addressed, requiring verification of AVC decision handling and potential updates to ensure proper SELinux functionality.

• Verification of AVC decision handling is required to ensure proper SELinux functionality
• Potential for undefined behavior in avc_audit() if AVC decision buffer is not properly initialized

Technical summary

The avc_has_perm_noaudit() function in the Linux kernel's SELinux implementation did not properly initialize the AVC decision buffer. This could lead to undefined behavior when the buffer was passed to avc_audit(). The issue has been resolved by filling in a deny-all, audit-all decision, similar to avd_init(), ensuring that every caller receives a defined value. This fix prevents potential crashes or unexpected behavior in SELinux-controlled systems and ensures proper auditing of SELinux policy decisions. Linux kernel developers should review the patch and apply it to affected systems.

Defensive priority

Medium

Recommended defensive actions

• Review and apply the patch from the Linux kernel Git repository
• Verify SELinux configuration and AVC decision handling
• Update Linux kernel to a version that includes the fix
• Perform thorough testing of SELinux functionality after applying the patch
• 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 Program record and NVD vulnerability detail page provide official information about this vulnerability. Multiple source references from the Linux kernel Git repository are also available. The issue is resolved in the Linux kernel through a patch that ensures the AVC decision buffer is properly initialized. Defenders should verify AVC decision handling and review SELinux configuration to ensure proper functionality. Additional verification of the patch application and system testing is recommended.

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.