Allocation of Resources Without Limits or Throttling Affecting microvm-kernel package, versions <1:6.1.189-236.399.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.18% (8th percentile)

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  • Snyk IDSNYK-AMZN2023-MICROVMKERNEL-21815035
  • published29 Oct 2026
  • disclosed23 Oct 2026

Introduced: 23 Oct 2026

NewCVE-2026-98900  (opens in a new tab)
CWE-770  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 microvm-kernel to version 1:6.1.189-236.399.amzn2023 or higher.
This issue was patched in ALAS2023-2026-3336.

NVD Description

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

xen/gntalloc: validate grant count before allocation

gntalloc_ioctl_alloc() allocates the grant-id array before checking whether the requested count fits within the global grant limit. Counts above that limit cannot succeed, so reject them before the user-controlled allocation reaches kcalloc().

Use a subtraction-based check while holding gref_mutex so adding the requested count cannot wrap. Also cast the count before advancing the per-file index so the page-size multiplication is performed in 64-bit arithmetic.

CVSS Base Scores

version 3.1