Out-of-bounds Write Affecting kernel6.18-debuginfo package, versions <1:6.18.54-121.166.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.2% (9th percentile)

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  • Snyk IDSNYK-AMZN2023-KERNEL618DEBUGINFO-21422706
  • published22 Oct 2026
  • disclosed6 Oct 2026

Introduced: 6 Oct 2026

NewCVE-2026-98248  (opens in a new tab)
CWE-787  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 kernel6.18-debuginfo to version 1:6.18.54-121.166.amzn2023 or higher.
This issue was patched in ALAS2023-2026-3192.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel6.18-debuginfo package and not the kernel6.18-debuginfo package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

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

arm64: percpu: Fix LSE operations on {8,16}-bit types

The assembly for _percpu##name##case##sz() and _percpu##name##return_case##sz() doesn't use the 'sfx' macro argument to form the LSE instruction. Without 'sfx', a W register argument will imply a 32-bit memory location, and consequently {8,16}-bit ops will erroneously read and write 32 bits of memory when the LSE instruction is used.

Fix this by appending 'sfx' to 'op_lse' to LSE instruction. It is not necessary (and not valid) to append 'sfx' to 'op_llsc', as 'op_llsc' is a register-register operation which does not access memory (and does not take a size suffix).

CVSS Base Scores

version 3.1