From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-68083: ksmbd: fix path resolution in ksmbd_vfs_kern_path_create
Date: Mon, 10 Aug 2026 13:40:21 +0200 [thread overview]
Message-ID: <2026081020-CVE-2026-68083-70ef@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix path resolution in ksmbd_vfs_kern_path_create
The SMB2 open lookup is rooted at the share with LOOKUP_BENEATH, but the
create/mkdir/hardlink sink is not: ksmbd_vfs_kern_path_create() builds an
absolute path with convert_to_unix_name() and resolves it from AT_FDCWD
via start_creating_path(), so a ".." component is walked from the real
filesystem root and escapes the export.
An authenticated client races a missing path component so the rooted open
lookup returns -ENOENT (taking the create branch) while the same component
is present (a directory) when the create walk runs; the create then
resolves ".." out of the share.
Root the create walk at the share like the lookup and rename paths already
are: resolve the parent with vfs_path_parent_lookup(..., LOOKUP_BENEATH,
&share_conf->vfs_path) and create the final component with
start_creating_noperm(). convert_to_unix_name() then has no callers and is
removed.
The Linux kernel CVE team has assigned CVE-2026-68083 to this issue.
Affected and fixed versions
===========================
Issue introduced in 5.15 with commit 265fd1991c1db85fbabaad4946ca0e63e2ae688d and fixed in 6.12.97 with commit 489d1ded01425c0fb33418172c0e4e588467526b
Issue introduced in 5.15 with commit 265fd1991c1db85fbabaad4946ca0e63e2ae688d and fixed in 6.18.40 with commit c7c884a1305aa4540eb7942a50bd356b34120e1f
Issue introduced in 5.15 with commit 265fd1991c1db85fbabaad4946ca0e63e2ae688d and fixed in 7.1.5 with commit 98185b3025beeae92d1fe700d5db26b9ac4bf025
Issue introduced in 5.15 with commit 265fd1991c1db85fbabaad4946ca0e63e2ae688d and fixed in 7.2-rc1 with commit 1c8951963d8ed357f70f59e0ad4ddce2199d2016
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-2026-68083
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/server/misc.c
fs/smb/server/misc.h
fs/smb/server/vfs.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/489d1ded01425c0fb33418172c0e4e588467526b
https://git.kernel.org/stable/c/c7c884a1305aa4540eb7942a50bd356b34120e1f
https://git.kernel.org/stable/c/98185b3025beeae92d1fe700d5db26b9ac4bf025
https://git.kernel.org/stable/c/1c8951963d8ed357f70f59e0ad4ddce2199d2016
reply other threads:[~2026-08-10 11:41 UTC|newest]
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