Improper Handling of Length Parameter Inconsistency Affecting microvm-kernel6.18 package, versions <1:6.18.35-68.127.amzn2023


Severity

Recommended
0.0
high
0
10

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.2% (10th percentile)

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  • Snyk IDSNYK-AMZN2023-MICROVMKERNEL618-18525692
  • published5 Aug 2026
  • disclosed19 Jul 2026

Introduced: 19 Jul 2026

CVE-2026-63940  (opens in a new tab)
CWE-130  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 microvm-kernel6.18 to version 1:6.18.35-68.127.amzn2023 or higher.
This issue was patched in ALAS2023-2026-1881.

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:

KVM: SEV: Ignore Port I/O requests of length '0'

Explicitly ignore Port I/O requests of length '0' (or count '0'), so that setting up the software scratch area (and other code) doesn't have to worry about underflowing the length, and to allow for WARNing on trying to configure the scratch area with len==0.

CVSS Base Scores

version 3.1