linux-cve-announce - CVE-2026-23044: PM: hibernate: Fix crash when freeing invalid crypto compressor

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Message-ID: <2026020439-CVE-2026-23044-3312@gregkh>
Date: Wed,  4 Feb 2026 17:00:44 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2026-23044: PM: hibernate: Fix crash when freeing invalid crypto compressor

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

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

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

PM: hibernate: Fix crash when freeing invalid crypto compressor

When crypto_alloc_acomp() fails, it returns an ERR_PTR value, not NULL.

The cleanup code in save_compressed_image() and load_compressed_image()
unconditionally calls crypto_free_acomp() without checking for ERR_PTR,
which causes crypto_acomp_tfm() to dereference an invalid pointer and
crash the kernel.

This can be triggered when the compression algorithm is unavailable
(e.g., CONFIG_CRYPTO_LZO not enabled).

Fix by adding IS_ERR_OR_NULL() checks before calling crypto_free_acomp()
and acomp_request_free(), similar to the existing kthread_stop() check.

[ rjw: Added 2 empty code lines ]

The Linux kernel CVE team has assigned CVE-2026-23044 to this issue.


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

	Issue introduced in 6.15 with commit b03d542c3c9569f549b1ba0cf7f4d90151fbf8ab and fixed in 6.18.6 with commit b7a883b0135dbc6817e90a829421c9fc8cd94bad
	Issue introduced in 6.15 with commit b03d542c3c9569f549b1ba0cf7f4d90151fbf8ab and fixed in 6.19-rc5 with commit 7966cf0ebe32c981bfa3db252cb5fc3bb1bf2e77

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-2026-23044
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:
	kernel/power/swap.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/b7a883b0135dbc6817e90a829421c9fc8cd94bad
	https://git.kernel.org/stable/c/7966cf0ebe32c981bfa3db252cb5fc3bb1bf2e77