# 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.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 4 Feb 2026
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2026-23044, DEBIAN-CVE-2026-23044, GHSA-fmhv-7w67-r8mw, UBUNTU-CVE-2026-23044

## 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.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-23044 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-23044 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-23044/ (Markdown: https://insights.sbomify.com/CVE-2026-23044/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23044
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23044
- OSV: https://osv.dev/vulnerability/CVE-2026-23044

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23044/
Summaries are generated and may contain mistakes; the official description above is the record.