CVE-2026-98862 Linux CVE debrief

Who should care

Linux kernel developers, administrators responsible for maintaining and securing Linux-based systems, and security teams should review and apply patches to prevent use-after-free errors. They should also monitor system logs for potential use-after-free errors and ensure that Linux kernel updates are properly tested and validated.

Why it matters

A use-after-free vulnerability in the Linux kernel's audit subsystem can cause system crashes or potentially allow attackers to execute arbitrary code. Linux kernel developers and administrators should review and apply patches to prevent use-after-free errors.

• Verify Linux kernel versions and apply patches to prevent use-after-free errors
• Monitor system logs for potential use-after-free errors
• Ensure that Linux kernel updates are properly tested and validated

Technical summary

The vulnerability exists in the Linux kernel's audit subsystem, specifically in the kill_rules() function. When an audit tree is pruned, mixed AUDIT_DIR and AUDIT_EXE rules are removed, but entry->rule.exe is dropped before removing the rule from RCU-visible filter lists. This can cause a use-after-free when another task is still evaluating the rule. The vulnerability has been resolved by unlinking published rules from RCU-visible lists and retaining them on tree->rules for cleanup. If any rule has an executable mark, the system waits for a single RCU grace period before removing the marks and scheduling the entries for freeing.

Defensive priority

Medium

Recommended defensive actions

• Review and apply the provided patches to the Linux kernel
• Ensure that the Linux kernel is updated to a version that includes the fix
• Monitor the system for potential use-after-free errors
• Verify Linux kernel versions and apply patches to prevent use-after-free errors
• Ensure that Linux kernel updates are properly tested and validated
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The vulnerability was introduced in the Linux kernel and has been resolved by unlinking published rules from RCU-visible lists and retaining them on tree->rules for cleanup. If any rule has an executable mark, the system waits for a single RCU grace period before removing the marks and scheduling the entries for freeing.

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.