Bug 2436800 (CVE-2026-23044)

Summary: CVE-2026-23044 kernel: PM: hibernate: Fix crash when freeing invalid crypto compressor
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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OS: Linux   
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A NULL pointer dereference vulnerability was found in the Linux kernel's hibernation subsystem. When crypto_alloc_acomp() fails and returns an ERR_PTR value, the cleanup code in save_compressed_image() and load_compressed_image() unconditionally calls crypto_free_acomp() without checking for the error. This causes crypto_acomp_tfm() to dereference the invalid pointer, crashing the kernel during hibernation operations.
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Description OSIDB Bzimport 2026-02-04 17:03:59 UTC 
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 ]
Comment 1 Jon Moroney 2026-02-04 21:46:00 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026020439-CVE-2026-23044-3312@gregkh/T