Bug 2554980 (CVE-2026-98638) - CVE-2026-98638 kernel: KVM: arm64: Validate the SVE vector length in pkvm_vcpu_init_sve()
Summary: CVE-2026-98638 kernel: KVM: arm64: Validate the SVE vector length in pkvm_vcp...
Keywords:
Status: NEW
Alias: CVE-2026-98638
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-10-18 15:37 UTC by OSIDB Bzimport
Modified: 2026-10-21 16:41 UTC (History)
17 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
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Description OSIDB Bzimport 2026-10-18 15:37:11 UTC
In the Linux kernel, the following vulnerability has been resolved:

KVM: arm64: Validate the SVE vector length in pkvm_vcpu_init_sve()

pkvm_vcpu_init_sve() clamps only the upper bound of the host-provided
sve_max_vl, so an invalid vector length reaches sve_state_size_from_vl()
and the WARN_ON() there, which is fatal at EL2. The existing
!sve_state_size test rejects such a length, but only after the macro has
run.

Check sve_vl_valid() before deriving the state size. A valid length
cannot yield a zero size, so the !sve_state_size test goes with it.


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