CVE-2026-98637Hinoki check available

NULL-state access via inconsistent SVE initialization flags

Published Oct 18, 2026 · Updated Oct 18, 2026

Linux 6.16 arm64 pKVM allows attackers to trigger a NULL state load after failed SVE initialization leaves VM flags inconsistent. pkvm_vcpu_init_sve() clears KVM_ARM_VCPU_SVE but leaves KVM_ARCH_FLAG_GUEST_HAS_SVE set, so later vCPUs skip setup and pass NULL sve_state to sve_load_state() on first floating-point access. This requires a host that misreports its vCPU state and is not reachable from host userspace; the disclosure does not specify the resulting interruption's scope.

CVSS severityUnavailable
Unscored
EPSS probability0.17%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Linux 6.16 arm64 pKVM allows attackers to trigger a NULL state load after failed SVE initialization leaves VM flags inconsistent. pkvm_vcpu_init_sve() clears KVM_ARM_VCPU_SVE but leaves KVM_ARCH_FLAG_GUEST_HAS_SVE set, so later vCPUs skip setup and pass NULL sve_state to sve_load_state() on first floating-point access. This requires a host that misreports its vCPU state and is not reachable from host userspace; the disclosure does not specify the resulting interruption's scope.

The record

CVE
CVE-2026-98637
Published
Oct 18, 2026
Updated
Oct 18, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Oct 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5db1bef933427aa467ad89c7b695a84a6b4afe16 <a1b3c788ad31837e348075e93dbba3f447492776
  2. Affected versionversion=5db1bef933427aa467ad89c7b695a84a6b4afe16 <bd46b41f412fb81c50bac1a0929ec31320f3a807
  3. Affected versionversion=5db1bef933427aa467ad89c7b695a84a6b4afe16 <f0cd8ffae092cc1b9d7cfa9188ed5a88a374adcb
  4. Affected versionversion=6.16

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=5db1bef933427aa467ad89c7b695a84a6b4afe16 <a1b3c788ad31837e348075e93dbba3f447492776; version=5db1bef933427aa467ad89c7b695a84a6b4afe16 <bd46b41f412fb81c50bac1a0929ec31320f3a807; version=5db1bef933427aa467ad89c7b695a84a6b4afe16 <f0cd8ffae092cc1b9d7cfa9188ed5a88a374adcb; version=6.16

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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