Bug 2451269 (CVE-2026-23391)

Summary:	CVE-2026-23391 kernel: netfilter: xt_CT: drop pending enqueued packets on template removal
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	Keywords:	Security
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Hardware:	All
OS:	Linux
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Doc Text:	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.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-03-25 11:08:04 UTC

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.

Comment 1 Alexander B 2026-03-25 11:56:10 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026032548-CVE-2026-23391-bb43@gregkh/T