Bug 2521388 (CVE-2026-74661)

Summary:	CVE-2026-74661 kernel: mac802154: fix netdev use-after-free in beacon worker
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
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 mac802154 component of the Linux kernel. This use-after-free vulnerability allows a local attacker to potentially cause a system crash (denial of service) or execute arbitrary code. The issue arises when the beacon worker attempts to access memory that has already been freed during network interface teardown.	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 2026-08-22 15:43:05 UTC

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

mac802154: fix netdev use-after-free in beacon worker

mac802154_beacon_worker() reads local->beacon_req under RCU and derives
the sub-interface from the request, but then drops the RCU read lock and
continues to use both sdata and the embedded wpan_dev.

mac802154_stop_beacons_locked() cancels only pending beacon work, clears
local->beacon_req and frees the request.  A beacon worker that is already
running can therefore continue after interface teardown and dereference
the freed netdev private area.

The scan worker already pins the netdev before leaving RCU.  Apply the
same lifetime rule to the beacon worker: take a netdev reference while
the request is still protected by RCU, and release it on all paths that
continue after the reference is acquired.

Comment 1 gkamathe 2026-08-24 10:44:16 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026082227-CVE-2026-74661-6885@gregkh/T