CVE-2026-64415 Linux CVE debrief

Who should care

Linux kernel users and administrators, especially those with large arm64 machines and heavy workloads, should be aware of this vulnerability and ensure they are running the patched kernel.

Technical summary

A softlockup vulnerability was found in the Linux kernel's swap_reclaim_full_clusters function. The vulnerability was caused by a lack of periodic cond_resched() calls during large full_clusters reclaim operations, leading to a softlockup. The issue was resolved by adding cond_resched() calls to prevent softlockup issues. The vulnerability was triggered during a stress test on a large arm64 machine with 320 CPUs, about 1TB memory, and an 8.6GB swap device under heavy load.

Defensive priority

Medium

Recommended defensive actions

• Apply the patched Linux kernel to prevent softlockup issues
• Monitor system logs for softlockup events
• Ensure the system is running with the latest kernel updates
• Review system configuration to prevent similar issues
• Check for any other potential vulnerabilities in the system
• Perform regular system maintenance to ensure stability
• Verify that the patched kernel is properly installed and configured

Evidence notes

The vulnerability was triggered during a stress test on a large arm64 machine with 320 CPUs, about 1TB memory, and an 8.6GB swap device under heavy load. The system was under heavy load and the swap device had a large number of full clusters. The vulnerability was resolved by adding cond_resched() calls to prevent softlockup issues.

Official resources