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Vulnerability · Published Oct 18, 2026 · Assigned by Linux

CVE-2026-98638KVM: arm64: Validate the SVE vector length in pkvm_vcpu_init_sve()

Unrated

In plain English

A security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 6% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS )–Not rated
Exploit odds (30 days)0.2%top 94.1% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:14linux7.2.9-1DEBIAN-CVE-2026-98638
Ubuntu:26.04:LTSlinux7.0.0-42.42UBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-98638
Ubuntu:26.04:LTSlinux-aws7.0.0-1016.17UBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-aws-7.0no fix listedUBUNTU-CVE-2026-98638
Ubuntu:26.04:LTSlinux-azureno fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-azure-7.0no fix listedUBUNTU-CVE-2026-98638
Ubuntu:26.04:LTSlinux-azure-fdeno fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-azure-fde-6.17no fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-azure-fde-7.0no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-98638
Ubuntu:26.04:LTSlinux-gcp7.0.0-1016.18UBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-gcp-7.0no fix listedUBUNTU-CVE-2026-98638
Ubuntu:26.04:LTSlinux-gkeno fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-hwe-7.07.0.0-42.42~24.04.1UBUNTU-CVE-2026-98638
Ubuntu:26.04:LTSlinux-ibm7.0.0-1017.17UBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-98638
Ubuntu:26.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-nvidia-7.0no fix listedUBUNTU-CVE-2026-98638
Ubuntu:26.04:LTSlinux-nvidia-bosno fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-98638
Ubuntu:26.04:LTSlinux-oem-7.07.0.0-1017.17UBUNTU-CVE-2026-98638
Ubuntu:26.04:LTSlinux-oracle7.0.0-1015.16UBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-oracle-7.0no fix listedUBUNTU-CVE-2026-98638
Ubuntu:26.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-98638
Ubuntu:26.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-98638
Ubuntu:26.04:LTSlinux-riscv7.0.0-42.42.1UBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-98638
Ubuntu:24.04:LTSlinux-riscv-7.07.0.0-42.42.1~24.04.1UBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-98638
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-98638

Affected products (as reported)

VendorProductVersions
Linux Linux 5db1bef933427aa467ad89c7b695a84a6b4afe16 – before faf66e55e87498ab4bf88cdf9a629e61b3f2d3bc5db1bef933427aa467ad89c7b695a84a6b4afe16 – before bae3e4493046de4fefa15f809d9b8dc114e84a3d5db1bef933427aa467ad89c7b695a84a6b4afe16 – before 2a2eb10795a1e495aebc7f829ccecb72c05b4fd9
Linux Linux 6.16

References