NULL Pointer Dereference Affecting kernel-64k-debug package, versions <0:5.14.0-284.11.1.el9_2


Severity

Recommended
high

Based on CentOS security rating.

Threat Intelligence

EPSS
0.02% (6th percentile)

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  • Snyk IDSNYK-CENTOS9-KERNEL64KDEBUG-13464973
  • published8 Oct 2025
  • disclosed7 Oct 2025

Introduced: 7 Oct 2025

NewCVE-2022-50530  (opens in a new tab)
CWE-476  (opens in a new tab)

How to fix?

Upgrade Centos:9 kernel-64k-debug to version 0:5.14.0-284.11.1.el9_2 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-64k-debug package and not the kernel-64k-debug package as distributed by Centos. See How to fix? for Centos:9 relevant fixed versions and status.

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().

CVSS Base Scores

version 3.1