{"id":"CVE-2026-64287","state":"PUBLISHED","title":"KVM: arm64: Bound used_lrs when flushing the pKVM hyp vCPU","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: Bound used_lrs when flushing the pKVM hyp vCPU\n\nflush_hyp_vcpu() copies the host vGIC state into the hyp's private vCPU\non every run. The vGIC list register save and restore use used_lrs as\ntheir loop bound and expect it to stay within the number of implemented\nlist registers. While this is generally the case, flush_hyp_vcpu()\ncopies vgic_v3 verbatim and does not enforce this, so a value provided\nby the host is used at EL2 to index vgic_lr[] and access ICH_LR<n>_EL2\n(host -> EL2).\n\nFix by clamping used_lrs to the number of implemented list registers\nafter the copy, as the trusted path already does in\nvgic_flush_lr_state(). The number of implemented list registers is\nconstant after init, so it is replicated once from\nkvm_vgic_global_state.nr_lr into hyp_gicv3_nr_lr rather than read on\nevery entry.","publishedAt":"2026-07-25T08:49:28.168Z","updatedAt":"2026-10-19T20:38:22.088Z","severity":{"score":8.2,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"be66e67f175096f283c9d5614c4991fc9e7ed975","status":"affected","lessThan":"2c5e72b9fbf83fdfa724e9f1af0f418ccf8739b8","versionType":"git"},{"version":"be66e67f175096f283c9d5614c4991fc9e7ed975","status":"affected","lessThan":"9fa301d8298778dd799fa4dcf7a7f440715d146e","versionType":"git"},{"version":"be66e67f175096f283c9d5614c4991fc9e7ed975","status":"affected","lessThan":"c646431865f4b1a5b14067233fa27b11e05e0d46","versionType":"git"},{"version":"be66e67f175096f283c9d5614c4991fc9e7ed975","status":"affected","lessThan":"7fca3fcef81c713bc82a37bf741e0f28e6d04a6f","versionType":"git"},{"version":"be66e67f175096f283c9d5614c4991fc9e7ed975","status":"affected","lessThan":"8cc8bbbfab14c22c5551d0dd19b208a44b141c76","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm64/include/asm/kvm_hyp.h","arch/arm64/kvm/arm.c","arch/arm64/kvm/hyp/nvhe/hyp-main.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.2","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.2","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.4","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm64/include/asm/kvm_hyp.h","arch/arm64/kvm/arm.c","arch/arm64/kvm/hyp/nvhe/hyp-main.c"]}],"references":["https://git.kernel.org/stable/c/2c5e72b9fbf83fdfa724e9f1af0f418ccf8739b8","https://git.kernel.org/stable/c/9fa301d8298778dd799fa4dcf7a7f440715d146e","https://git.kernel.org/stable/c/c646431865f4b1a5b14067233fa27b11e05e0d46","https://git.kernel.org/stable/c/7fca3fcef81c713bc82a37bf741e0f28e6d04a6f","https://git.kernel.org/stable/c/8cc8bbbfab14c22c5551d0dd19b208a44b141c76"],"weaknesses":["CWE-125"],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64287.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64287","state":"PUBLISHED","datePublished":"2026-07-25T08:49:28.168Z","dateUpdated":"2026-10-19T20:38:22.088Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T15:36:31.778Z"},"containers":{"cna":{"title":"KVM: arm64: Bound used_lrs when flushing the pKVM hyp vCPU","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: Bound used_lrs when flushing the pKVM hyp vCPU\n\nflush_hyp_vcpu() copies the host vGIC state into the hyp's private vCPU\non every run. The vGIC list register save and restore use used_lrs as\ntheir loop bound and expect it to stay within the number of implemented\nlist registers. While this is generally the case, flush_hyp_vcpu()\ncopies vgic_v3 verbatim and does not enforce this, so a value provided\nby the host is used at EL2 to index vgic_lr[] and access ICH_LR<n>_EL2\n(host -> EL2).\n\nFix by clamping used_lrs to the number of implemented list registers\nafter the copy, as the trusted path already does in\nvgic_flush_lr_state(). The number of implemented list registers is\nconstant after init, so it is replicated once from\nkvm_vgic_global_state.nr_lr into hyp_gicv3_nr_lr rather than read on\nevery entry."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"be66e67f175096f283c9d5614c4991fc9e7ed975","status":"affected","lessThan":"2c5e72b9fbf83fdfa724e9f1af0f418ccf8739b8","versionType":"git"},{"version":"be66e67f175096f283c9d5614c4991fc9e7ed975","status":"affected","lessThan":"9fa301d8298778dd799fa4dcf7a7f440715d146e","versionType":"git"},{"version":"be66e67f175096f283c9d5614c4991fc9e7ed975","status":"affected","lessThan":"c646431865f4b1a5b14067233fa27b11e05e0d46","versionType":"git"},{"version":"be66e67f175096f283c9d5614c4991fc9e7ed975","status":"affected","lessThan":"7fca3fcef81c713bc82a37bf741e0f28e6d04a6f","versionType":"git"},{"version":"be66e67f175096f283c9d5614c4991fc9e7ed975","status":"affected","lessThan":"8cc8bbbfab14c22c5551d0dd19b208a44b141c76","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm64/include/asm/kvm_hyp.h","arch/arm64/kvm/arm.c","arch/arm64/kvm/hyp/nvhe/hyp-main.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.2","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.2","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.4","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/arm64/include/asm/kvm_hyp.h","arch/arm64/kvm/arm.c","arch/arm64/kvm/hyp/nvhe/hyp-main.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/2c5e72b9fbf83fdfa724e9f1af0f418ccf8739b8"},{"url":"https://git.kernel.org/stable/c/9fa301d8298778dd799fa4dcf7a7f440715d146e"},{"url":"https://git.kernel.org/stable/c/c646431865f4b1a5b14067233fa27b11e05e0d46"},{"url":"https://git.kernel.org/stable/c/7fca3fcef81c713bc82a37bf741e0f28e6d04a6f"},{"url":"https://git.kernel.org/stable/c/8cc8bbbfab14c22c5551d0dd19b208a44b141c76"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H","baseScore":8.2,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - A malicious or compromised arm64 EL1 host reaches the flaw through the local KVM vCPU-run hypercall into pKVM EL2. No network or adjacent protocol directly controls this internal field.\nAC:L - On a pKVM/GICv3 system, the host can directly select an oversized used_lrs value and deterministically trigger the unchecked loops. No race or condition outside the attacker's control is required.\nPR:H - Normal KVM paths keep used_lrs hardware-bounded, and neither an unprivileged KVM user nor a user namespace can assign it directly. Exploitation requires control of the host kernel at EL1, equivalent to real administrative privileges.\nUI:N - The malicious host can load and run a vCPU itself without any action by a protected-VM user or another victim.\nS:C - Exploitation crosses pKVM's EL1-host-to-EL2 isolation boundary and can affect hypervisor-private state and protected VMs outside the host's security authority.\nC:H - The restore and synchronization paths can read beyond vgic_lr[] and transfer hyp-private vCPU data back into host-visible memory. EL2 compromise could expose protected-VM memory and other hypervisor secrets.\nI:H - The save path writes beyond vgic_lr[] into adjacent hyp-private vCPU metadata, including pointer, lock, and list state. This memory corruption is plausibly usable for EL2 control-flow hijacking and protected-VM modification.\nA:H - Large bounds can cause extensive loops, invalid EL2 memory accesses, or corruption of critical hypervisor metadata. An nVHE hypervisor panic explicitly escalates to a host kernel panic."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T04:52:43.106Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.6.145"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.12.97"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"7.1.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-64287","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:38:27.178822Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-125","lang":"en","type":"CWE","description":"CWE-125 Out-of-bounds Read"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T20:38:22.088Z"}}]}}}