linux-cve-announce - CVE-2025-68761: hfs: fix potential use after free in hfs_correct_next_unused

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Message-ID: <2026010551-CVE-2025-68761-7f01@gregkh>
Date: Mon,  5 Jan 2026 10:32:57 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-68761: hfs: fix potential use after free in hfs_correct_next_unused_CNID()

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

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

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

hfs: fix potential use after free in hfs_correct_next_unused_CNID()

This code calls hfs_bnode_put(node) which drops the refcount and then
dreferences "node" on the next line.  It's only safe to use "node"
when we're holding a reference so flip these two lines around.

The Linux kernel CVE team has assigned CVE-2025-68761 to this issue.


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

	Issue introduced in 6.18 with commit a06ec283e125e334155fe13005c76c9f484ce759 and fixed in 6.18.2 with commit 40a1e0142096dd7dd6cb5373841222b528698588
	Issue introduced in 6.18 with commit a06ec283e125e334155fe13005c76c9f484ce759 and fixed in 6.19-rc1 with commit c105e76bb17cf4b55fe89c6ad4f6a0e3972b5b08

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-2025-68761
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/hfs/catalog.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/40a1e0142096dd7dd6cb5373841222b528698588
	https://git.kernel.org/stable/c/c105e76bb17cf4b55fe89c6ad4f6a0e3972b5b08