VulnerabilityPublished 23 Oct 2026

CVE-2026-98928: Linux kernel · KVM: arm64: Derive GUEST_HAS_SVE from the SVE feature bit at EL2

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in 7b5e99d286747b6b5b583b8efcd06bdbdd94b229 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 17:30 UTC

Severity

Medium

Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 7b5e99d286747b6b5b583b8efcd06bdbdd94b229, 4f16c5fc8dc4c5596e3777ab9f449a54e3f85fd5, 4efda204087145d40a84344edec7e9d3885ad3ab

Exploitation evidence

Disclosed: evidence found.
CVE published 23 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Linux kernel to 7b5e99d286747b6b5b583b8efcd06bdbdd94b229, 4f16c5fc8dc4c5596e3777ab9f449a54e3f85fd5 or 4efda204087145d40a84344edec7e9d3885ad3ab.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 41d6028e28bd474298ff10409c292ec46cf43a90, < 7b5e99d286747b6b5b583b8efcd06bdbdd94b229	Fixed in 7b5e99d286747b6b5b583b8efcd06bdbdd94b229
LinuxLinux	Affected ≥ 41d6028e28bd474298ff10409c292ec46cf43a90, < 4f16c5fc8dc4c5596e3777ab9f449a54e3f85fd5	Fixed in 4f16c5fc8dc4c5596e3777ab9f449a54e3f85fd5
LinuxLinux	Affected ≥ 41d6028e28bd474298ff10409c292ec46cf43a90, < 4efda204087145d40a84344edec7e9d3885ad3ab	Fixed in 4efda204087145d40a84344edec7e9d3885ad3ab
LinuxLinux	Affected =6.14	Fixed in–

AI-suggested

A fix is available and has been applied in the Linux kernel commits referenced. Users should update to a Linux kernel version that includes these fixes. No additional mitigation actions are indicated.

Description

A vulnerability in the Linux kernel's KVM arm64 implementation related to the handling of the SVE feature bit at EL2 has been resolved. The issue involved inconsistent derivation of the GUEST_HAS_SVE flag, which could lead to a vCPU with a NULL SVE state being loaded incorrectly. The fix derives the flag directly from the SVE feature bit and removes redundant code for protected VMs that do not support SVE.

Impact

The vulnerability could cause a virtual CPU to have a NULL SVE state when the host sets the GUEST_HAS_SVE flag without the corresponding SVE feature bit, potentially leading to incorrect loading of the guest's SVE state. This could affect the stability or correctness of virtual machines using SVE on arm64 architecture under KVM. No known exploits in the wild have been reported.

Summary

In Linux kernel version 6.14, the KVM arm64 code had a flaw where the GUEST_HAS_SVE flag was taken separately from the SVE feature bit at EL2, causing inconsistencies. Specifically, pkvm_init_features_from_host() took the flag and the SVE vCPU flag separately, but pkvm_vcpu_init_sve() tested the bit directly, and vcpu_has_sve() read the flag. This mismatch could result in a virtual CPU with a NULL sve_state, which the world switch would attempt to load as the guest's SVE state. The patch derives the GUEST_HAS_SVE flag directly from the SVE feature bit and removes the protected path's copy of the host's flag, which was dead code since protected VMs are not allowed SVE. The issue is fixed in commits identified by hashes 7b5e99d286747b6b5b583b8efcd06bdbdd94b229, 4f16c5fc8dc4c5596e3777ab9f449a54e3f85fd5, and 4efda204087145d40a84344edec7e9d3885ad3ab.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 15:33 UTC

Technical details

References

Community reviews

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