Bug 2482561 (CVE-2026-46233)

Summary:	CVE-2026-46233 kernel: batman-adv: bla: only purge non-released claims
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	unspecified	CC:	rhel-process-autobot, 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 batman-adv module. This vulnerability allows a local attacker to trigger a NULL-pointer dereference within the `batadv_bla_purge_claims()` function. This issue arises from a timing conflict when a claim is being released simultaneously, causing a critical pointer to become invalid. Successful exploitation of this flaw can lead to a system crash, resulting in a denial of service (DoS).	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 2026-05-28 11:03:20 UTC

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

batman-adv: bla: only purge non-released claims

When batadv_bla_purge_claims() goes through the list of claims, it is only
traversing the hash list with an rcu_read_lock(). Due to a potential
parallel batadv_claim_put(), it can happen that it encounters a claim which
was actually in the process of being released+freed by
batadv_claim_release(). In this case, backbone_gw is set to NULL before the
delayed RCU kfree is started. Calling batadv_bla_claim_get_backbone_gw() is
then no longer allowed because it would cause a NULL-ptr derefence.

To avoid this, only claims with a valid reference counter must be purged.
All others are already taken care of.

Comment 1 Keith Grant 2026-05-28 12:20:40 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026052840-CVE-2026-46233-1e33@gregkh/T