CVE-2026-80735: ovpn: ensure socket is owned by ovpn before deref sk_user_data

CVE-2026-80735: ovpn: ensure socket is owned by ovpn before deref sk_user_data

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

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

ovpn: ensure socket is owned by ovpn before deref sk_user_data

Some subsystems, like BPF SOCKMAP, set sk_user_data without
actually setting the encap_type.

For this reason, we must make sure that the type is the
one ovpn expects before dereferencing sk_user_data.

Failing to do so may lead to out-of-bounds reads.

The Linux kernel CVE team has assigned CVE-2026-80735 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.16 with commit f6226ae7a0cd47aaa9175aca6a1e19600f884cbf and fixed in 6.18.45 with commit 61fb3cca40ff938671474f4a16adb908c19032d7
	Issue introduced in 6.16 with commit f6226ae7a0cd47aaa9175aca6a1e19600f884cbf and fixed in 7.1.9 with commit 43a31142e1d22b3cf5490bd94a94db7196901734
	Issue introduced in 6.16 with commit f6226ae7a0cd47aaa9175aca6a1e19600f884cbf and fixed in 7.2 with commit 59aed1eb60d70678a53acccb0cb337a26ce6680e

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-80735
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/net/ovpn/socket.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/61fb3cca40ff938671474f4a16adb908c19032d7
	https://git.kernel.org/stable/c/43a31142e1d22b3cf5490bd94a94db7196901734
	https://git.kernel.org/stable/c/59aed1eb60d70678a53acccb0cb337a26ce6680e