CVE-2026-64100 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, users of Linux kernel versions affected by this vulnerability, and security teams responsible for patching and vulnerability management should review and apply the patch provided by the Linux kernel maintainers. They should also monitor systems for potential exploitation attempts and verify the effectiveness of the fix.

Technical summary

The Linux kernel's drm/msm component has a deadlock vulnerability. When kswapd0 holding fs_reclaim calls the MSM shrinker, it calls dma_resv_lock, which acquires fs_reclaim, resulting in a deadlock. The fix replaces dma_resv_lock with dma_resv_trylock(), dropping the unused wait-wound lock 'ticket'. This change prevents the deadlock by avoiding the acquisition of fs_reclaim while holding reservation_ww_class_acquire. The patch provided by the Linux kernel maintainers should be reviewed and applied to affected systems.

Defensive priority

High priority for Linux kernel developers and maintainers to patch the vulnerability.

Recommended defensive actions

• Review and apply the patch provided by the Linux kernel maintainers.
• Update Linux kernel versions to include the fix.
• Monitor systems for potential exploitation attempts.
• Verify the effectiveness of the fix.
• 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.
• Review compensating controls for exposed systems while remediation is scheduled and verified.

Evidence notes

The vulnerability was resolved by using dma_resv_trylock() instead of dma_resv_lock. The fix was applied to the Linux kernel. This change prevents the deadlock by avoiding the acquisition of fs_reclaim while holding reservation_ww_class_acquire. Linux kernel developers and maintainers should verify the patch and apply it to affected systems. Evidence limits suggest that the fix is effective, but further verification is needed to confirm that it does not introduce new issues.

Official resources