---
id: CVE-2026-98638
title: 'KVM: arm64: Validate the SVE vector length in pkvm_vcpu_init_sve()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  KVM: arm64: Validate the SVE vector length in pkvm_vcpu_init_sve()

  pkvm_vcpu_init_sve() clamps only the upper bound of the host-provided
  sve_max_vl, so an invalid vect…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 5db1bef933427aa467ad89c7b695a84a6b4afe16 <
    faf66e55e87498ab4bf88cdf9a629e61b3f2d3bc
  - >-
    Linux >= 5db1bef933427aa467ad89c7b695a84a6b4afe16 <
    bae3e4493046de4fefa15f809d9b8dc114e84a3d
  - >-
    Linux >= 5db1bef933427aa467ad89c7b695a84a6b4afe16 <
    2a2eb10795a1e495aebc7f829ccecb72c05b4fd9
  - Linux 6.16
published: '2026-10-18'
updated: '2026-10-18'
sourceUpdated: '2026-10-18T15:20:09.380Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-98638'
references:
  - url: 'https://git.kernel.org/stable/c/faf66e55e87498ab4bf88cdf9a629e61b3f2d3bc'
  - url: 'https://git.kernel.org/stable/c/bae3e4493046de4fefa15f809d9b8dc114e84a3d'
  - url: 'https://git.kernel.org/stable/c/2a2eb10795a1e495aebc7f829ccecb72c05b4fd9'
tags:
  - cve.org
ingestedAt: '2026-10-18T15:45:12.232Z'
---

## Overview

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

KVM: arm64: Validate the SVE vector length in pkvm_vcpu_init_sve()

pkvm_vcpu_init_sve() clamps only the upper bound of the host-provided
sve_max_vl, so an invalid vector length reaches sve_state_size_from_vl()
and the WARN_ON() there, which is fatal at EL2. The existing
!sve_state_size test rejects such a length, but only after the macro has
run.

Check sve_vl_valid() before deriving the state size. A valid length
cannot yield a zero size, so the !sve_state_size test goes with it.

## Affected

- `Linux >= 5db1bef933427aa467ad89c7b695a84a6b4afe16 < faf66e55e87498ab4bf88cdf9a629e61b3f2d3bc`
- `Linux >= 5db1bef933427aa467ad89c7b695a84a6b4afe16 < bae3e4493046de4fefa15f809d9b8dc114e84a3d`
- `Linux >= 5db1bef933427aa467ad89c7b695a84a6b4afe16 < 2a2eb10795a1e495aebc7f829ccecb72c05b4fd9`
- `Linux 6.16`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.