cve 2026 31418

CVE-2026-31418 is a Linux kernel vulnerability affecting netfilter ipset. The bug occurs in the mtype_del() function, which fails to treat a bucket as empty when its live entries have been removed but n->pos still points past deleted slots. This can lead to operational issues in firewall and network filtering setups. The fix involves releasing a logically empty bucket instead of attempting further shrinking. While the flaw is narrowly scoped, it sits in a critical part of the networking stack where small accounting mistakes can cause real problems. This tag covers discussions about the vulnerability, its technical details, and the patch that resolves it.