From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-64136: smb: client: protect tc_count increment in smb2_find_smb_sess_tcon_unlocked()
Date: Sun, 19 Jul 2026 17:39:58 +0200 [thread overview]
Message-ID: <2026071928-CVE-2026-64136-5fb4@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
smb: client: protect tc_count increment in smb2_find_smb_sess_tcon_unlocked()
Commit 96c4af418586 ("cifs: Fix locking usage for tcon fields")
refactored cifs code to change cifs_tcp_ses_lock for tc_lock around
tc_count changes.
There was missing lock around tc_count increment inside
smb2_find_smb_sess_tcon_unlocked().
The Linux kernel CVE team has assigned CVE-2026-64136 to this issue.
Affected and fixed versions
===========================
Issue introduced in 6.6.128 with commit 953953abb66e52c224057ab91e404284fefeab62 and fixed in 6.6.142 with commit 7df1df6f40c0720d30206aa35c0343b962350e0d
Issue introduced in 6.12.75 with commit 601dd3b79769b38d30b693c40afdb2a4b7edf9d0 and fixed in 6.12.92 with commit 13fb413ae22a37c69341918a6d651d19a9b0b9b7
Issue introduced in 6.18.16 with commit 3969db6b22e3d90d8c5f22ac1a7fe0350a94c136 and fixed in 6.18.34 with commit bf4ebdb19ff9b3cdf992b50715fe61633327416a
Issue introduced in 7.0 with commit 96c4af418586ee9a6aab61738644366426e05316 and fixed in 7.0.11 with commit e374f4e496fef8168784f93a4477d67be34485fd
Issue introduced in 7.0 with commit 96c4af418586ee9a6aab61738644366426e05316 and fixed in 7.1 with commit 4d8690dace005a38e6dbde9ecce2da3ad85c7c41
Issue introduced in 6.19.6 with commit 8c59eeeeffa1524ef57e173a89a1a3ff539888d5
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-2026-64136
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:
fs/smb/client/smb2transport.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/7df1df6f40c0720d30206aa35c0343b962350e0d
https://git.kernel.org/stable/c/13fb413ae22a37c69341918a6d651d19a9b0b9b7
https://git.kernel.org/stable/c/bf4ebdb19ff9b3cdf992b50715fe61633327416a
https://git.kernel.org/stable/c/e374f4e496fef8168784f93a4477d67be34485fd
https://git.kernel.org/stable/c/4d8690dace005a38e6dbde9ecce2da3ad85c7c41
reply other threads:[~2026-07-19 15:45 UTC|newest]
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