CVE-2026-98638
Published Oct 18, 2026
Description
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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References
Frequently Asked Questions
What is CVE-2026-98638? +
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.
How do I check if I'm vulnerable to CVE-2026-98638? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.