Bug 2513235 (CVE-2026-68342)

Summary:	CVE-2026-68342 kernel: ovpn: avoid putting unrelated P2P peer on socket release
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:	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 OpenVPN (ovpn) module. During the destruction of an ovpn UDP socket, a race condition can occur where a new peer is published before the old socket is fully released. This can lead to a use-after-free vulnerability, allowing an attacker to potentially cause a denial of service or execute arbitrary code by manipulating memory that has been deallocated.	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 2026-08-10 12:26:19 UTC

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

ovpn: avoid putting unrelated P2P peer on socket release

ovpn_peer_release_p2p() is called when an OVPN UDP socket is being
destroyed. It checks the currently published P2P peer and releases it only
if that peer still uses the socket being destroyed.

A peer replacement can publish a new peer before the old UDP socket is
destroyed. When the old socket destruction path runs afterwards,
ovpn_peer_release_p2p() observes the new peer through ovpn->peer. Since the
new peer uses a different socket, the function takes the socket mismatch
branch.

That branch still calls ovpn_peer_put(peer). At this point, however, peer
is the currently published replacement peer, not the peer associated with
the socket being destroyed. Dropping its reference can free it while
ovpn->peer still points to it, leading to later use-after-free accesses
from the peer and socket cleanup paths.

KASAN reports this as a slab-use-after-free on the kmalloc-1k ovpn_peer
object. In the reproducer, the object is allocated from ovpn_peer_new() via
ovpn_nl_peer_new_doit(), and freed through ovpn_peer_release_rcu() from RCU
callback processing. Observed access sites include ovpn_peer_remove(),
ovpn_socket_release(), ovpn_nl_peer_del_notify(), and unlock_ovpn().

Fix this by returning from the socket mismatch branch without putting the
peer.