Bug 2546494 (CVE-2026-98320)

Summary:	CVE-2026-98320 kernel: netfilter: flowtable: hold reference on ct until flow is released
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's netfilter subsystem. In the flowtable component, connection tracking reference counts are prematurely released before flow entries are fully removed from memory. An attacker could exploit this timing issue during network flow processing, triggering a use-after-free condition. This issue primarily leads to a Denial of Service (DoS) via a system crash or unexpected system instability.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-10-06 09:32:37 UTC

In the Linux kernel, the following vulnerability has been resolved:

netfilter: flowtable: hold reference on ct until flow is released

nf_ct_put() releases the ct->ext area inmediately, the rcu typesafe
semantics also allow to refer to the wrong conntrack from the flowtable
datapath. Hold reference on ct until flow is released after rcu grace
period.

Add rcu_barrier() on module exit path, to ensure pending flow entries
are release before module goes away.

Comment 1 gkamathe 2026-10-10 03:59:14 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98320.mbox