Bug 2477055 (CVE-2026-43481)

Summary:	CVE-2026-43481 kernel: net-shapers: don't free reply skb after genlmsg_reply()
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	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 `net-shapers` component. An issue exists where the `skb` (socket buffer) is freed twice if `genlmsg_reply()` fails, leading to a double-free vulnerability. This can result in memory corruption or a denial of service (DoS) condition, potentially allowing a local attacker to impact system stability.	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 2026-05-13 16:01:43 UTC

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

net-shapers: don't free reply skb after genlmsg_reply()

genlmsg_reply() hands the reply skb to netlink, and
netlink_unicast() consumes it on all return paths, whether the
skb is queued successfully or freed on an error path.

net_shaper_nl_get_doit() and net_shaper_nl_cap_get_doit()
currently jump to free_msg after genlmsg_reply() fails and call
nlmsg_free(msg), which can hit the same skb twice.

Return the genlmsg_reply() error directly and keep free_msg
only for pre-reply failures.

Comment 1 Vipul Nair 2026-05-13 16:50:51 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026051348-CVE-2026-43481-6f80@gregkh/T