From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-80733: net: remove WARN_ON_ONCE() from sk_mc_loop()
Date: Thu, 3 Sep 2026 10:22:02 +0200 [thread overview]
Message-ID: <2026090358-CVE-2026-80733-06eb@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
net: remove WARN_ON_ONCE() from sk_mc_loop()
sk_mc_loop() can be called for sockets that are neither AF_INET
nor AF_INET6 (e.g. AF_PACKET sockets when sending packets via raw/packet
socket over virtual devices such as VRF or ipvlan).
In such cases, sk_family is not AF_INET/AF_INET6 and sk_mc_loop() falls
through the switch statement and triggers WARN_ON_ONCE(1).
Non-INET sockets do not support IP_MULTICAST_LOOP or IPV6_MULTICAST_LOOP
options, so loopback should default to true without generating a warning.
The Linux kernel CVE team has assigned CVE-2026-80733 to this issue.
Affected and fixed versions
===========================
Issue introduced in 4.0 with commit f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 and fixed in 5.10.265 with commit 97133c4d42654578fab95abe47359ebe784dde18
Issue introduced in 4.0 with commit f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 and fixed in 5.15.216 with commit f625c742b33dc137c209dd13d1c5f12b1c18d71c
Issue introduced in 4.0 with commit f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 and fixed in 6.1.183 with commit ad7fa2f411cb30f63d6725f111be134064cdb718
Issue introduced in 4.0 with commit f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 and fixed in 6.6.152 with commit d2adc4e80b29e58b5162ae09f0f657a215806c8c
Issue introduced in 4.0 with commit f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 and fixed in 6.12.104 with commit ad7dbb1d14b1b4406eca8ef9478e8de312ba0cfe
Issue introduced in 4.0 with commit f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 and fixed in 6.18.45 with commit c8f256dc849205ccb2bd78bd99a3497b972b44e0
Issue introduced in 4.0 with commit f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 and fixed in 7.1.9 with commit 0d75f2c1d0764efa756ad9c1e078d8c09ea8fc1f
Issue introduced in 4.0 with commit f60e5990d9c1424af9dbca60a23ba2a1c7c1ce90 and fixed in 7.2 with commit b8a39a09ae4eaae04309e1e38ed6a1101d967496
Issue introduced in 3.14.40 with commit c91f81773cd4bbebfe744e9ab30a7ce093f9b930
Issue introduced in 3.18.13 with commit c8c30b2b17f2133e953850c547e3902c3a3d80e2
Issue introduced in 3.19.6 with commit 3fe207e4637a2e792c46a08666aa722f77d7f8f7
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-2026-80733
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:
net/core/sock.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/97133c4d42654578fab95abe47359ebe784dde18
https://git.kernel.org/stable/c/f625c742b33dc137c209dd13d1c5f12b1c18d71c
https://git.kernel.org/stable/c/ad7fa2f411cb30f63d6725f111be134064cdb718
https://git.kernel.org/stable/c/d2adc4e80b29e58b5162ae09f0f657a215806c8c
https://git.kernel.org/stable/c/ad7dbb1d14b1b4406eca8ef9478e8de312ba0cfe
https://git.kernel.org/stable/c/c8f256dc849205ccb2bd78bd99a3497b972b44e0
https://git.kernel.org/stable/c/0d75f2c1d0764efa756ad9c1e078d8c09ea8fc1f
https://git.kernel.org/stable/c/b8a39a09ae4eaae04309e1e38ed6a1101d967496
reply other threads:[~2026-09-03 8:22 UTC|newest]
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