Linux KVM: NULL sve_state on VCPU from GUEST_HAS_SVE flag bug
CVE-2026-98928 Published on October 23, 2026
KVM: arm64: Derive GUEST_HAS_SVE from the SVE feature bit at EL2
In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Derive GUEST_HAS_SVE from the SVE feature bit at EL2
pkvm_init_features_from_host() takes KVM_ARCH_FLAG_GUEST_HAS_SVE and
KVM_ARM_VCPU_SVE from the host separately, but pkvm_vcpu_init_sve()
tests the bit while vcpu_has_sve() reads the flag. A host that sets the
flag without the bit gets a vCPU with a NULL sve_state that the world
switch loads the guest's SVE state from.
Derive the flag from the bit, and drop the protected path's copy of the
host's flag, which is dead code since protected VMs are not allowed SVE.
Products Associated with CVE-2026-98928
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Affected Versions
Linux:- Version 41d6028e28bd474298ff10409c292ec46cf43a90 and below 4efda204087145d40a84344edec7e9d3885ad3ab is affected.
- Version 41d6028e28bd474298ff10409c292ec46cf43a90 and below 7b5e99d286747b6b5b583b8efcd06bdbdd94b229 is affected.
- Version 41d6028e28bd474298ff10409c292ec46cf43a90 and below 4f16c5fc8dc4c5596e3777ab9f449a54e3f85fd5 is affected.
- Version 6.14 is affected.
- Before 6.14 is unaffected.
- Version 6.18.55, <= 6.18.* is unaffected.
- Version 7.2.9, <= 7.2.* is unaffected.
- Version 7.3, <= * is unaffected.