From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-80982: net/smc: fix use-after-free in smc_rx_pipe_buf_release()
Date: Fri, 11 Sep 2026 21:41:28 +0200 [thread overview]
Message-ID: <2026091146-CVE-2026-80982-45b7@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
net/smc: fix use-after-free in smc_rx_pipe_buf_release()
smc_rx_splice() hands RMB pages to a pipe and takes a socket reference
per entry so the smc_sock stays alive until the reader finishes. The
connection does not: a concurrent close runs smc_conn_free(), which
releases the receive buffer back to the link group pool.
smc_rx_pipe_buf_release() tests sk_state before taking the socket lock.
The state can change between the test and the lock, and
smc_rx_update_cons() then dereferences conn->rmb_desc and walks
conn->lgr, which smc_conn_free() has already released. On the
is_reg_err path smcr_buf_unuse() frees the descriptor outright, so
this is a use-after-free.
Take the socket lock first and test conn->freed instead.
smc_conn_free() sets that flag before releasing anything, and every
caller holds the socket lock. The two paths exclude each other: either
the pipe release runs first with everything valid, or it sees the flag
and skips the update.
The Linux kernel CVE team has assigned CVE-2026-80982 to this issue.
Affected and fixed versions
===========================
Issue introduced in 4.18 with commit 9014db202cb764b8e14c53e7bacc81f9a1a2ba7f and fixed in 6.12.109 with commit 6a644a7340df978785f3109d1e0726a982ce2c6f
Issue introduced in 4.18 with commit 9014db202cb764b8e14c53e7bacc81f9a1a2ba7f and fixed in 6.18.50 with commit 0761e49aa78c2f1362511054c6e9670653858837
Issue introduced in 4.18 with commit 9014db202cb764b8e14c53e7bacc81f9a1a2ba7f and fixed in 7.2.4 with commit 0926f59ca0f94120895b92180c636a48d0ed3a6d
Issue introduced in 4.18 with commit 9014db202cb764b8e14c53e7bacc81f9a1a2ba7f and fixed in 7.3-rc1 with commit c924884743e948e25625b7fbf3ee2a9325a204a7
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-2026-80982
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/smc/smc_rx.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/6a644a7340df978785f3109d1e0726a982ce2c6f
https://git.kernel.org/stable/c/0761e49aa78c2f1362511054c6e9670653858837
https://git.kernel.org/stable/c/0926f59ca0f94120895b92180c636a48d0ed3a6d
https://git.kernel.org/stable/c/c924884743e948e25625b7fbf3ee2a9325a204a7
reply other threads:[~2026-09-11 19:48 UTC|newest]
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