VulnerabilityPublished 26 Oct 2026Updated 27 Oct 2026

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

Affects Linux kernelSource GCVE Database

Authoritative record:CVE-2026-98928· Medium

Not known to be exploited.

Data as of 28 Oct 2026, 02:27 UTC

Severity

Medium

Rated by Threat Radar · CVSS not yet scored by NVD

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

Affected software

Product	Affected	Fixed in
Ubuntu 26.04 LTSlinux`pkg:deb/ubuntu/linux?arch=source&distro=resolute`Other threats	Affected 6.17.0-5.5 – 7.0.0-38.38 23 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1014.14 15 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=resolute`Other threats	Affected 6.17.0-1003.3 – 7.0.0-1017.17 15 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-azure-fde`pkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resolute`Other threats	Affected 7.0.0-1003.3 – 7.0.0-1016.16 9 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=resolute`Other threats	Affected 6.17.0-1002.2 – 7.0.0-1014.14 13 affected builds	Fixed in–
Ubuntu 26.04 LTSlinux-gke`pkg:deb/ubuntu/linux-gke?arch=source&distro=resolute`Other threats	Affected 7.0.0-1002.3 – 7.0.0-1008.9 6 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix has been implemented in the Linux kernel to derive the GUEST_HAS_SVE flag from the SVE feature bit at EL2, eliminating the inconsistent flag handling. Users should update to a patched kernel version that includes this fix. No additional mitigation steps are required beyond applying the official kernel update.

Description

A vulnerability in the Linux kernel's KVM arm64 implementation involves incorrect handling of the SVE feature bit at EL2. The issue arises because the guest's SVE flag is derived separately from the host's SVE feature bit, leading to a situation where a virtual CPU (vCPU) may have a NULL SVE state. This can cause the world switch to load the guest's SVE state improperly. The vulnerability has been resolved by deriving the guest's SVE flag directly from the feature bit and removing redundant code related to protected VMs.

Impact

This vulnerability could cause improper handling of the Scalable Vector Extension (SVE) state in virtual CPUs on arm64 architectures, potentially leading to incorrect guest state loading during context switches. The impact is limited to KVM guests on arm64 hosts with SVE enabled and protected VMs are not affected due to the removal of dead code. No known exploits in the wild have been reported.

Summary

The Linux kernel's KVM arm64 code previously took the GUEST_HAS_SVE flag and the KVM_ARM_VCPU_SVE flag from the host separately, causing inconsistency. Specifically, pkvm_init_features_from_host() used separate flags, while pkvm_vcpu_init_sve() tested the feature bit and vcpu_has_sve() read the flag. This mismatch allowed a host setting the flag without the corresponding feature bit to create a vCPU with a NULL sve_state, which the world switch then used to load the guest's SVE state incorrectly. The fix derives the GUEST_HAS_SVE flag directly from the SVE feature bit at EL2 and removes the protected path's copy of the host's flag, which was dead code since protected VMs are not allowed SVE.

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 28 Oct 2026, 02:27 UTC

Technical details

References

Community reviews

Related threats