CVE-2026-64040: cachefiles: Fix error return when vfs_mkdir() fails

Greg Kroah-Hartman <[email protected]>
Newsgroups org.kernel.vger.linux-cve-announce
Message-ID <2026071906-CVE-2026-64040-6908@gregkh>
From: Greg Kroah-Hartman <[email protected]>

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

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

cachefiles: Fix error return when vfs_mkdir() fails

When vfs_mkdir() fails, the error code is not extracted from the
returned error pointer. This causes mkdir_error to be reached with
ret=0, which leads to returning ERR_PTR(0) (NULL) instead of a
proper error pointer.

Fix this by extracting the error code from the error pointer when
vfs_mkdir() fails.

The Linux kernel CVE team has assigned CVE-2026-64040 to this issue.


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

	Issue introduced in 6.15 with commit 406fad7698f5bf21ab6b5ca195bf4b9e0b3990ed and fixed in 7.0.11 with commit 0940108d27c6995e02819ff832be11892f0b208b
	Issue introduced in 6.15 with commit 406fad7698f5bf21ab6b5ca195bf4b9e0b3990ed and fixed in 7.1 with commit 8a220d1c312c66194f4a33dd52d1fba42bc2b341

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-2026-64040
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/cachefiles/namei.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/0940108d27c6995e02819ff832be11892f0b208b
	https://git.kernel.org/stable/c/8a220d1c312c66194f4a33dd52d1fba42bc2b341
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