Improper Validation of Specified Index, Position, or Offset in Input Affecting microvm-kernel6.18 package, versions <1:6.18.56-125.164.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.17% (6th percentile)

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  • Snyk IDSNYK-AMZN2023-MICROVMKERNEL618-21804485
  • published29 Oct 2026
  • disclosed18 Oct 2026

Introduced: 18 Oct 2026

NewCVE-2026-98856  (opens in a new tab)
CWE-1285  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 microvm-kernel6.18 to version 1:6.18.56-125.164.amzn2023 or higher.
This issue was patched in ALAS2023-2026-3251.

NVD Description

Note: Versions mentioned in the description apply only to the upstream microvm-kernel6.18 package and not the microvm-kernel6.18 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:

kprobes: Skip disarmed probes when checking optkprobe overlap

On x86, an optkprobe at A replaces five bytes with a jump. If a disabled probe B is at A+2, get_optimized_kprobe() stops at B when arming a new probe C at A+4. It leaves A optimized:

          A    A+1  A+2  A+3  A+4

A's jump | e9 | d0 | d1 | d2 | d3 | after C | e9 | d0 | d1 | d2 | cc |

The INT3 for C overwrites the last byte of A's jump displacement, so execution can jump to the wrong address. B can have prepared optinsns while disarmed, but has no jump to unoptimize.

Continue past disarmed and unprepared probes to find the active optimized probe before arming a probe in its jump.

CVSS Base Scores

version 3.1