# CVE-2026-98928: Linux kernel KVM arm64 SVE feature flag inconsistency

Source: https://junglewise.ai/threats/cve-2026-98928-in-the-linux-kernel-the-following-vulnerability-has-been-resolved  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-23. Updated: 2026-10-23  
License: CC BY 4.0 with a link back

CVE-2026-98928 · Severity: info · Published 2026-10-23

A bug in the Linux kernel's KVM hypervisor on ARM64 systems causes inconsistent handling of Scalable Vector Extension (SVE) feature flags for virtual machines. When SVE support is configured inconsistently, a guest VM may operate with uninitialized SVE state, potentially leading to data corruption or hypervisor instability.

Technologies: [Linux kernel](https://junglewise.ai/threats/technologies/x-linux-kernel).

## Quick answers

**Is CVE-2026-98928 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-98928 being exploited in the wild.

**How severe is CVE-2026-98928?** Informational severity, published 23 October 2026.

**Which products and versions are affected?** Linux kernel 5.10 and later.

**Is there a fix for CVE-2026-98928?** A patch was published on 2026-09-15: Upstream commit 4f16c5fc8dc4c5596e3777ab9f449a54e3f85fd5 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-98928 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-98928?** Check whether you run Linux kernel at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability exists in pkvm_init_features_from_host() where KVM_ARCH_FLAG_GUEST_HAS_SVE and KVM_ARM_VCPU_SVE are handled separately by different code paths. A host system that sets the flag without the corresponding bit results in a vCPU with NULL sve_state, which the world switch then attempts to load guest SVE data from. The fix derives the flag from the bit and consolidates the logic to ensure consistency.

## Affected products

- Linux kernel 5.10 and later

## Timeline

- 2026-10-23: disclosed
- 2026-09-15: patched: Upstream commit 4f16c5fc8dc4c5596e3777ab9f449a54e3f85fd5

## References

- [https://git.kernel.org/stable/c/4efda204087145d40a84344edec7e9d3885ad3ab](https://git.kernel.org/stable/c/4efda204087145d40a84344edec7e9d3885ad3ab)
- [https://git.kernel.org/stable/c/4f16c5fc8dc4c5596e3777ab9f449a54e3f85fd5](https://git.kernel.org/stable/c/4f16c5fc8dc4c5596e3777ab9f449a54e3f85fd5)

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