From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-98683: smb: client: flush dirty data before zeroing a range
Date: Sun, 18 Oct 2026 17:44:18 +0200 [thread overview]
Message-ID: <2026101801-CVE-2026-98683-9df4@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
smb: client: flush dirty data before zeroing a range
smb3_zero_range() emulates FALLOC_FL_ZERO_RANGE by invalidating the
page cache over the target range with truncate_pagecache_range() and
then issuing FSCTL_SET_ZERO_DATA to the server.
Dirty data was only flushed conditionally, when the range reached or
extended EOF. For a purely interior zero range that does not reach
EOF, no flush happened, so a dirty folio overlapping the range could
be written back to the server after the FSCTL and refill the range
that was just zeroed with stale data.
Fix this by unconditionally flushing and waiting for dirty data in the
range before invalidating the page cache and issuing
FSCTL_SET_ZERO_DATA, exactly as was done for smb3_punch_hole() in
commit d7d2adcd022b ("smb/client: flush dirty data before punching a
hole"); the two paths are structurally identical here.
This is observed as generic/363 randomly reading stale data where a
zeroed range is expected against Windows Server.
The Linux kernel CVE team has assigned CVE-2026-98683 to this issue.
Affected and fixed versions
===========================
Issue introduced in 6.11 with commit 91d1dfae464987aaf6c79ff51d8674880fb3be77 and fixed in 6.18.56 with commit cecf4114069fc19629d284710fd783d56bbca862
Issue introduced in 6.11 with commit 91d1dfae464987aaf6c79ff51d8674880fb3be77 and fixed in 7.2.10 with commit e8ba21c7e6ef3d4cb617858760673877b2e4a2bb
Issue introduced in 6.11 with commit 91d1dfae464987aaf6c79ff51d8674880fb3be77 and fixed in 7.3-rc6 with commit 8f8d32c1044f70e46e87550e039a15ff20a4b21c
Issue introduced in 6.1.110 with commit 13af7446428771e9e529284d390e7994df8be683
Issue introduced in 6.6.51 with commit 0a9423f99ded38b32bd1864347332cc557e6b141
Issue introduced in 6.10.10 with commit 7dfa4279c55f467a88e653a5d544817181b22aea
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-2026-98683
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/smb2ops.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/cecf4114069fc19629d284710fd783d56bbca862
https://git.kernel.org/stable/c/e8ba21c7e6ef3d4cb617858760673877b2e4a2bb
https://git.kernel.org/stable/c/8f8d32c1044f70e46e87550e039a15ff20a4b21c
reply other threads:[~2026-10-18 15:48 UTC|newest]
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