CVE-2026-64006 Linux CVE debrief

Who should care

Users of the Linux kernel, particularly those who use netfilter: nf_tables for packet filtering and processing, should be aware of this vulnerability and take steps to mitigate it. This includes reviewing the Linux kernel's implementation, testing the patched version, and applying the fix as soon as possible.

Technical summary

The vulnerability is caused by the incorrect calculation of the carry for the next iteration in the lshift and rshift operations. This is due to the fact that the carry is calculated using the newly modified dst value instead of the original src value when src and dst point to the same memory location. The fix adds a temporary local variable to cache the original value before writing to dst and uses it for the carry calculation. This change prevents the corruption of the dst value and ensures that the carry is calculated correctly.

Defensive priority

Medium-High

Recommended defensive actions

• Apply the patch
• Monitor for updates
• 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
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance

Evidence notes

The vulnerability was resolved by adding a temporary local variable to cache the original value before writing to dst and using it for the carry calculation. This change prevents the incorrect calculation of the carry for the next iteration in the lshift and rshift operations when src and dst point to the same memory location. The fix ensures that the carry is calculated using the original src value instead of the newly modified dst value. To verify, defenders should review the Linux kernel's netfilter: nf_tables implementation and test the patched version with relevant test cases.

Official resources