Improper Locking Affecting kernel-debug package, versions *


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.17% (5th percentile)

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  • Snyk IDSNYK-RHEL6-KERNELDEBUG-21975020
  • published30 Oct 2026
  • disclosed16 Sept 2026

Introduced: 16 Sep 2026

CVE-2026-90046  (opens in a new tab)
CWE-667  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:6 kernel-debug.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-debug package and not the kernel-debug package as distributed by RHEL. See How to fix? for RHEL:6 relevant fixed versions and status.

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

mm/page_alloc: don't spin_trylock() in NMI on UP

Patch series "mm/page_alloc: fixes for free_pages_nolock() on RT/UP".

Pre-existing bugs found by Sashiko during review of this other series: https://lore.kernel.org/all/20260703-alloc-trylock-v5-0-c87b714e19d3@google.com/

I have not reproduced these bugs, and I suspect there is no real-world user that is affected by them.

This patch (of 2):

As noted in can_spin_trylock(), using this is unsafe in this context. commit 620b46ed6ae17 ("mm/page_alloc: return NULL early from alloc_frozen_pages_nolock() in NMI on UP") fixed this on the alloc side but missed the free side.

Impact: If BPF programs using these features in NMI (probably tracing) are present on non-SMP builds this might crash the kernel and is probably exploitable by local attackers for privilege escalation.

CVSS Base Scores

version 3.1