{"id":"CVE-2026-64286","state":"PUBLISHED","title":"KVM: arm64: Clear __hyp_running_vcpu when flushing the pKVM hyp vCPU","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: Clear __hyp_running_vcpu when flushing the pKVM hyp vCPU\n\nflush_hyp_vcpu() copies the host vCPU context into the hyp's private\nvCPU on every run. ctxt_to_vcpu() expects a guest context to have a\nNULL __hyp_running_vcpu, which is only ever set on the host context, so\nthat it resolves the vCPU via container_of(). While this is generally\nthe case, flush_hyp_vcpu() copies the context verbatim and does not\nenforce this, so a value provided by the host is dereferenced at EL2\n(host -> EL2).\n\nFix by clearing __hyp_running_vcpu after the copy.","publishedAt":"2026-07-25T08:49:27.542Z","updatedAt":"2026-10-19T20:38:21.930Z","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":"477145860dba4c30f0b4e36f02f4c5291c1c888b","versionType":"git"},{"version":"be66e67f175096f283c9d5614c4991fc9e7ed975","status":"affected","lessThan":"dfaef40d8a1533940fc1af788d70fce07362b4ce","versionType":"git"},{"version":"be66e67f175096f283c9d5614c4991fc9e7ed975","status":"affected","lessThan":"6bea2f8becdb20d34378493c3b77a9b9cf8c6cfa","versionType":"git"},{"version":"be66e67f175096f283c9d5614c4991fc9e7ed975","status":"affected","lessThan":"d4f4d61715d1061ba83b88196a3605662be30750","versionType":"git"},{"version":"be66e67f175096f283c9d5614c4991fc9e7ed975","status":"affected","lessThan":"e8042f6e1d7befb2fb6b10a75918642bcd0acf9a","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["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":"6.18.39","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/kvm/hyp/nvhe/hyp-main.c"]}],"references":["https://git.kernel.org/stable/c/477145860dba4c30f0b4e36f02f4c5291c1c888b","https://git.kernel.org/stable/c/dfaef40d8a1533940fc1af788d70fce07362b4ce","https://git.kernel.org/stable/c/6bea2f8becdb20d34378493c3b77a9b9cf8c6cfa","https://git.kernel.org/stable/c/d4f4d61715d1061ba83b88196a3605662be30750","https://git.kernel.org/stable/c/e8042f6e1d7befb2fb6b10a75918642bcd0acf9a"],"weaknesses":["CWE-822"],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64286.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64286","state":"PUBLISHED","datePublished":"2026-07-25T08:49:27.542Z","dateUpdated":"2026-10-19T20:38:21.930Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T15:36:31.778Z"},"containers":{"cna":{"title":"KVM: arm64: Clear __hyp_running_vcpu when flushing the pKVM hyp vCPU","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: Clear __hyp_running_vcpu when flushing the pKVM hyp vCPU\n\nflush_hyp_vcpu() copies the host vCPU context into the hyp's private\nvCPU on every run. ctxt_to_vcpu() expects a guest context to have a\nNULL __hyp_running_vcpu, which is only ever set on the host context, so\nthat it resolves the vCPU via container_of(). While this is generally\nthe case, flush_hyp_vcpu() copies the context verbatim and does not\nenforce this, so a value provided by the host is dereferenced at EL2\n(host -> EL2).\n\nFix by clearing __hyp_running_vcpu after the copy."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"be66e67f175096f283c9d5614c4991fc9e7ed975","status":"affected","lessThan":"477145860dba4c30f0b4e36f02f4c5291c1c888b","versionType":"git"},{"version":"be66e67f175096f283c9d5614c4991fc9e7ed975","status":"affected","lessThan":"dfaef40d8a1533940fc1af788d70fce07362b4ce","versionType":"git"},{"version":"be66e67f175096f283c9d5614c4991fc9e7ed975","status":"affected","lessThan":"6bea2f8becdb20d34378493c3b77a9b9cf8c6cfa","versionType":"git"},{"version":"be66e67f175096f283c9d5614c4991fc9e7ed975","status":"affected","lessThan":"d4f4d61715d1061ba83b88196a3605662be30750","versionType":"git"},{"version":"be66e67f175096f283c9d5614c4991fc9e7ed975","status":"affected","lessThan":"e8042f6e1d7befb2fb6b10a75918642bcd0acf9a","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["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":"6.18.39","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/kvm/hyp/nvhe/hyp-main.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/477145860dba4c30f0b4e36f02f4c5291c1c888b"},{"url":"https://git.kernel.org/stable/c/dfaef40d8a1533940fc1af788d70fce07362b4ce"},{"url":"https://git.kernel.org/stable/c/6bea2f8becdb20d34378493c3b77a9b9cf8c6cfa"},{"url":"https://git.kernel.org/stable/c/d4f4d61715d1061ba83b88196a3605662be30750"},{"url":"https://git.kernel.org/stable/c/e8042f6e1d7befb2fb6b10a75918642bcd0acf9a"}],"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 local EL1 host can place the pointer in the host vCPU context and trigger the vulnerable pKVM path through KVM_RUN; no remote input path reaches it.\nAC:L - The attacker-selected pointer is copied and dereferenced deterministically on every vCPU run, without a race, and EL2 addresses of host-donated metadata are derivable by the host.\nPR:H - Exploitation requires host-kernel control or an equivalent arbitrary kernel write. The KVM userspace register API does not expose __hyp_running_vcpu, and user namespaces do not bypass this restriction.\nUI:N - Once the malicious host context is prepared, invoking the vCPU run path requires no action by another user.\nS:C - The vulnerability crosses the intended isolation boundary from the untrusted EL1 host into the pKVM hypervisor at EL2 and can affect protected-VM resources.\nC:H - The forged pointer drives EL2-private memory dereferences during system-register restoration. Chaining these reads with the write-side corruption can compromise EL2 and expose hypervisor or protected-guest memory.\nI:H - The system-register save path can write through the attacker-selected vCPU pointer into EL2-accessible memory. This can corrupt trusted hypervisor metadata and plausibly enable control-flow or protected-guest state modification.\nA:H - An invalid or unmapped pointer causes a synchronous EL2 fault followed by the nVHE HYP panic handler, which explicitly panics the host kernel."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T04:52:42.012Z"},"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":"6.18.39"},{"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-2026-64286","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:38:23.510778Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-822","lang":"en","type":"CWE","description":"CWE-822 Untrusted Pointer Dereference"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T20:38:21.930Z"}}]}}}