CVE-2026-31407: Linux Kernel

High severity, CVSS 7.1. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: netfilter: conntrack: add missing netlink policy validations Hyunwoo Kim reports out-of-bounds access in sctp and ctnetlink. These attributes are used by the kernel without any validation. Extend the netlink policies accordingly. Quoting the reporter: nlattr_to_sctp() assigns the user-supplied CTA_PROTOINFO_SCTP_STATE value directly to ct->proto.sctp.state without checking that it is within the valid range. [..] and: ... with exp->dir = 100, the access at ct->master->tuplehash[100] reads 5600 bytes past the start of a 320-byte nf_conn object, causing a slab-out-of-bounds read confirmed by UBSAN.

Affected products

• Linux Linux Kernel: from 2.6.27, before 6.6.136 (fixed in 6.6.136); from 6.7, before 6.12.83 (fixed in 6.12.83); from 6.13, before 6.18.24 (fixed in 6.18.24); from 6.19, before 6.19.10 (fixed in 6.19.10); version 7.0 only

Published 2026-04-06. Last modified 2026-07-24.