From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-89642: cifs: call pagecache_isize_extended() in cifs_setsize() when extending
Date: Fri, 11 Sep 2026 21:45:31 +0200 [thread overview]
Message-ID: <2026091142-CVE-2026-89642-c3b3@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
cifs: call pagecache_isize_extended() in cifs_setsize() when extending
cifs_setsize() calls truncate_pagecache() but skips
pagecache_isize_extended() on extension. truncate_setsize() shows
the correct pattern:
i_size_write(inode, newsize);
if (newsize > oldsize)
pagecache_isize_extended(inode, oldsize, newsize);
truncate_pagecache(inode, newsize);
pagecache_isize_extended() zeroes the tail of the page straddling old
EOF. Without it, dirty bytes in that region can be written back to
the server, exposing stale data in the newly extended range.
The Linux kernel CVE team has assigned CVE-2026-89642 to this issue.
Affected and fixed versions
===========================
Fixed in 7.2.4 with commit 12bafe32f09c0d24f5096154b59c347b9c6606e0
Fixed in 7.3-rc1 with commit c510edb9734af1c274d18f4f31a471a166bbc7e8
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-2026-89642
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/inode.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/12bafe32f09c0d24f5096154b59c347b9c6606e0
https://git.kernel.org/stable/c/c510edb9734af1c274d18f4f31a471a166bbc7e8
reply other threads:[~2026-09-11 20:00 UTC|newest]
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