Bug 2461761 (CVE-2026-31678)

Summary:	CVE-2026-31678 kernel: openvswitch: defer tunnel netdev_put to RCU release
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 Linux kernel's Open vSwitch (OVS) component. A race condition can occur during the destruction of a network device (netdev) tunnel, where the `ovs_netdev_tunnel_destroy()` function may attempt to release a device reference while other parts of the system are still actively using it. This timing issue, or race condition, could lead to system instability or a denial of service (DoS) due to improper resource handling.	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 2026-04-25 09:01:48 UTC

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

openvswitch: defer tunnel netdev_put to RCU release

ovs_netdev_tunnel_destroy() may run after NETDEV_UNREGISTER already
detached the device. Dropping the netdev reference in destroy can race
with concurrent readers that still observe vport->dev.

Do not release vport->dev in ovs_netdev_tunnel_destroy(). Instead, let
vport_netdev_free() drop the reference from the RCU callback, matching
the non-tunnel destroy path and avoiding additional synchronization
under RTNL.

Comment 1 Alexander B 2026-04-27 10:51:52 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026042544-CVE-2026-31678-79f5@gregkh/T