CVE-2026-23044 PM: hibernate: Fix crash when freeing invalid crypto compressor
A local attacker can crash the Linux kernel by triggering a null pointer dereference in the hibernation code when the LZO compression algorithm is unavailable.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-23044?
CVE-2026-23044 is a vulnerability in Linux, published on 4 Feb 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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 ]
Which versions are affected by CVE-2026-23044?
How do I fix CVE-2026-23044?
Apply the vendor's patch.
Is CVE-2026-23044 being exploited?
There is no known exploitation of CVE-2026-23044 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-23044, DEBIAN-CVE-2026-23044, GHSA-fmhv-7w67-r8mw, UBUNTU-CVE-2026-23044.