CVE-2026-31418

Description

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.

References

• https://git.kernel.org/stable/c/68ca0eea0af02bed36c5e2c13e9fa1647c31a7d4
• https://git.kernel.org/stable/c/6cea34d7ec6829b62f521a37a287f670144a2233
• https://git.kernel.org/stable/c/9862ef9ab0a116c6dca98842aab7de13a252ae02
• https://git.kernel.org/stable/c/ad92ee87462f9a3061361d392e9dbfe2e5c1c9fb
• https://git.kernel.org/stable/c/b7eef00f08b92b0b9efe8ae0df6d0005e6199323