CVE-2026-64286 (GCVE-0-2026-64286)
Vulnerability from cvelistv5
Published
2026-07-25 08:49
Modified
2026-08-17 04:52
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Clear __hyp_running_vcpu when flushing the pKVM hyp vCPU
flush_hyp_vcpu() copies the host vCPU context into the hyp's private
vCPU on every run. ctxt_to_vcpu() expects a guest context to have a
NULL __hyp_running_vcpu, which is only ever set on the host context, so
that it resolves the vCPU via container_of(). While this is generally
the case, flush_hyp_vcpu() copies the context verbatim and does not
enforce this, so a value provided by the host is dereferenced at EL2
(host -> EL2).
Fix by clearing __hyp_running_vcpu after the copy.
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"arch/arm64/kvm/hyp/nvhe/hyp-main.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "477145860dba4c30f0b4e36f02f4c5291c1c888b",
"status": "affected",
"version": "be66e67f175096f283c9d5614c4991fc9e7ed975",
"versionType": "git"
},
{
"lessThan": "dfaef40d8a1533940fc1af788d70fce07362b4ce",
"status": "affected",
"version": "be66e67f175096f283c9d5614c4991fc9e7ed975",
"versionType": "git"
},
{
"lessThan": "6bea2f8becdb20d34378493c3b77a9b9cf8c6cfa",
"status": "affected",
"version": "be66e67f175096f283c9d5614c4991fc9e7ed975",
"versionType": "git"
},
{
"lessThan": "d4f4d61715d1061ba83b88196a3605662be30750",
"status": "affected",
"version": "be66e67f175096f283c9d5614c4991fc9e7ed975",
"versionType": "git"
},
{
"lessThan": "e8042f6e1d7befb2fb6b10a75918642bcd0acf9a",
"status": "affected",
"version": "be66e67f175096f283c9d5614c4991fc9e7ed975",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"arch/arm64/kvm/hyp/nvhe/hyp-main.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.2"
},
{
"lessThan": "6.2",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.39",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.4",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.145",
"versionStartIncluding": "6.2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.97",
"versionStartIncluding": "6.2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.39",
"versionStartIncluding": "6.2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.4",
"versionStartIncluding": "6.2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "6.2",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"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\u0027s 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 -\u003e EL2).\n\nFix by clearing __hyp_running_vcpu after the copy."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.2,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H",
"version": "3.1"
},
"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": {
"dateUpdated": "2026-08-17T04:52:42.012Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"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"
}
],
"title": "KVM: arm64: Clear __hyp_running_vcpu when flushing the pKVM hyp vCPU",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-64286",
"datePublished": "2026-07-25T08:49:27.542Z",
"dateReserved": "2026-07-19T15:36:31.778Z",
"dateUpdated": "2026-08-17T04:52:42.012Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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