NULL Pointer Dereference Affecting kernel-debug-modules-internal package, versions *


Severity

Recommended
0.0
medium
0
10

Based on CentOS security rating.

Threat Intelligence

EPSS
0.19% (9th percentile)

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  • Snyk IDSNYK-CENTOS8-KERNELDEBUGMODULESINTERNAL-21503751
  • published23 Oct 2026
  • disclosed16 Sept 2026

Introduced: 16 Sep 2026

CVE-2026-89856  (opens in a new tab)
CWE-476  (opens in a new tab)

How to fix?

There is no fixed version for Centos:8 kernel-debug-modules-internal.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-debug-modules-internal package and not the kernel-debug-modules-internal package as distributed by Centos. See How to fix? for Centos:8 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

scsi: qla2xxx: Clamp MSI-X derived queue counts to avoid truncation

ha->msix_count is u16, but ha->max_req_queues, ha->max_rsp_queues and ha->max_qpairs are u8. Deriving the queue count as "ha->max_req_queues = ha->msix_count - 1" therefore truncates: a board (or a misconfigured/malicious hot-plugged device) advertising 257 MSI-X vectors yields msix_count - 1 == 256, which truncates to 0. An MSI-X count of 1 zeroes it as well, and in target mode the subsequent "ha->max_req_queues--" then underflows 0 to 255.

When the count is 0, qla2x00_alloc_queues() calls kzalloc_objs(struct req_que *, 0), which returns ZERO_SIZE_PTR. That is not NULL, so the allocation check passes and the following "ha->req_q_map[0] = req" dereferences ZERO_SIZE_PTR, corrupting memory or crashing the kernel.

Add qla_calc_queue_count() to clamp the derived value into [1, QLA_MAX_QUEUES - 1] so it always fits in u8 and is never zero, and use it at all three derivation sites (qla25xx_iospace_config(), qla83xx_iospace_config() and qla24xx_enable_msix()). Also guard the target-mode decrement so it cannot reintroduce a zero (which would in turn underflow max_qpairs).

CVSS Base Scores

version 3.1