linux-cve-announce - CVE-2025-38431: smb: client: fix regression with native SMB symlinks

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Message-ID: <2025072537-CVE-2025-38431-9bb6@gregkh>
Date: Fri, 25 Jul 2025 16:22:37 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-38431: smb: client: fix regression with native SMB symlinks

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

smb: client: fix regression with native SMB symlinks

Some users and customers reported that their backup/copy tools started
to fail when the directory being copied contained symlink targets that
the client couldn't parse - even when those symlinks weren't followed.

Fix this by allowing lstat(2) and readlink(2) to succeed even when the
client can't resolve the symlink target, restoring old behavior.

The Linux kernel CVE team has assigned CVE-2025-38431 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.14 with commit 12b466eb52d926802b6898d2cb7e67386467f54a and fixed in 6.15.5 with commit 6ddaf7567080c7de2e0c99efca2ee1e6b79beea5
	Issue introduced in 6.14 with commit 12b466eb52d926802b6898d2cb7e67386467f54a and fixed in 6.16-rc4 with commit ff8abbd248c1f52df0c321690b88454b13ff54b2

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-2025-38431
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/reparse.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/6ddaf7567080c7de2e0c99efca2ee1e6b79beea5
	https://git.kernel.org/stable/c/ff8abbd248c1f52df0c321690b88454b13ff54b2