Linux Kernel up to 6.18.5/6.19-rc4 crypto_alloc_acomp null pointer dereference

Summaryinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.18.5/6.19-rc4. Impacted is the function crypto_alloc_acomp. The manipulation results in null pointer dereference. This vulnerability is identified as CVE-2026-23044. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 6.18.5/6.19-rc4. Affected is the function crypto_alloc_acomp. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. CVE summarizes:

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 advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2026-23044 since 01/13/2026. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 297930 (Linux Distros Unpatched Vulnerability : CVE-2026-23044), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.18.6 or 6.19-rc5 eliminates this vulnerability. Applying the patch b7a883b0135dbc6817e90a829421c9fc8cd94bad/7966cf0ebe32c981bfa3db252cb5fc3bb1bf2e77 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (297930) and CERT Bund (WID-SEC-2026-0324). Once again VulDB remains the best source for vulnerability data.

Affected

• Debian Linux
• Google Cloud Platform
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• IBM QRadar SIEM
• SUSE openSUSE
• RESF Rocky Linux
• Open Source Linux Kernel

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.19-rc1
• 6.19-rc2
• 6.19-rc3
• 6.19-rc4

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Once again VulDB remains the best source for vulnerability data.

Discussion