CVE-2026-31418: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 0.1% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: netfilter: ipset: drop logically empty buckets in mtype_del mtype_del() counts empty slots below n->pos in k, but it only drops the bucket when both n->pos and k are zero. This misses buckets whose live entries have all been removed while n->pos still points past deleted slots. Treat a bucket as empty when all positions below n->pos are unused and release it directly instead of shrinking it further.

Affected products

• Linux Linux Kernel: from 5.4.24, before 5.5 (fixed in 5.5); from 5.5.8, before 5.6 (fixed in 5.6); from 5.6.1, before 5.10.253 (fixed in 5.10.253); from 5.11, before 5.15.203 (fixed in 5.15.203); from 5.16, before 6.1.168 (fixed in 6.1.168); from 6.2, before 6.6.134 (fixed in 6.6.134); …

Published 2026-04-13. Last modified 2026-07-14.