Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-03-25T00:00:00 kernel: netfilter: xt_CT: drop pending enqueued packets on template removal 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CWE-911

In the Linux kernel, the following vulnerability has been resolved: netfilter: xt_CT: drop pending enqueued packets on template removal Templates refer to objects that can go away while packets are sitting in nfqueue refer to: - helper, this can be an issue on module removal. - timeout policy, nfnetlink_cttimeout might remove it. The use of templates with zone and event cache filter are safe, since this just copies values. Flush these enqueued packets in case the template rule gets removed.

A flaw was found in the Linux kernel’s netfilter subsystem. When a netfilter template rule is removed, packets that are still queued and refer to the removed template are not properly dropped. This improper handling of packets could lead to resource exhaustion or unexpected system behavior, potentially resulting in a denial of service.

This flaw affects systems using nfqueue with connection tracking templates. When templates referencing helpers or timeout policies are removed while packets are queued, those packets can reference freed objects. The issue occurs during module removal or timeout policy deletion while traffic is being processed via nfqueue. Red Hat Enterprise Linux 10 Fix deferred kernel Red Hat Enterprise Linux 6 Out of support scope kernel Red Hat Enterprise Linux 7 Fix deferred kernel Red Hat Enterprise Linux 7 Fix deferred kernel-rt Red Hat Enterprise Linux 8 Fix deferred kernel Red Hat Enterprise Linux 8 Fix deferred kernel-rt Red Hat Enterprise Linux 9 Fix deferred kernel Red Hat Enterprise Linux 9 Fix deferred kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-23391 https://nvd.nist.gov/vuln/detail/CVE-2026-23391 https://lore.kernel.org/linux-cve-announce/2026032548-CVE-2026-23391-bb43@gregkh/T