Linux Kernel up to 6.0.5 blk_mq_clear_rq_mapping null pointer dereference

Summaryinfo

A vulnerability categorized as critical has been discovered in Linux Kernel up to 6.0.5. This affects the function blk_mq_clear_rq_mapping. Executing a manipulation can lead to null pointer dereference. This vulnerability is tracked as CVE-2022-50530. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.0.5. This vulnerability affects the function blk_mq_clear_rq_mapping. The manipulation with an unknown input leads to a null pointer dereference vulnerability. The CWE definition for the vulnerability is 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. As an impact it is known to affect availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: blk-mq: fix null pointer dereference in blk_mq_clear_rq_mapping() Our syzkaller report a null pointer dereference, root cause is following: __blk_mq_alloc_map_and_rqs set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs blk_mq_alloc_map_and_rqs blk_mq_alloc_rqs // failed due to oom alloc_pages_node // set->tags[hctx_idx] is still NULL blk_mq_free_rqs drv_tags = set->tags[hctx_idx]; // null pointer dereference is triggered blk_mq_clear_rq_mapping(drv_tags, ...) This is because commit 63064be150e4 ("blk-mq: Add blk_mq_alloc_map_and_rqs()") merged the two steps: 1) set->tags[hctx_idx] = blk_mq_alloc_rq_map() 2) blk_mq_alloc_rqs(..., set->tags[hctx_idx]) into one step: set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs() Since tags is not initialized yet in this case, fix the problem by checking if tags is NULL pointer in blk_mq_clear_rq_mapping().

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2022-50530 since 10/07/2025. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 302981 (EulerOS Virtualization 2.13.1 : kernel (EulerOS-SA-2026-1637)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.0.6 eliminates this vulnerability. Applying the patch 6a440e6d04431e774dc084abe88c106e2a474c1a/76dd298094f484c6250ebd076fa53287477b2328 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 (302981) and CERT Bund (WID-SEC-2025-2229). Once again VulDB remains the best source for vulnerability data.

Affected

• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• RESF Rocky Linux
• Open Source Linux Kernel
• IBM QRadar SIEM
• Dell NetWorker

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.0.0
• 6.0.1
• 6.0.2
• 6.0.3
• 6.0.4
• 6.0.5

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Once again VulDB remains the best source for vulnerability data.

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