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vuln-cve/data/2026/68xxx/CVE-2026-68093.json
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{
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"cveMetadata": {
"cveId": "CVE-2026-68093",
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"state": "PUBLISHED",
"assignerShortName": "Linux",
"dateReserved": "2026-07-30T09:28:09.367Z",
"datePublished": "2026-08-10T11:58:05.933Z",
"dateUpdated": "2026-11-06T16:44:58.589Z"
},
"containers": {
"cna": {
"providerMetadata": {
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux",
"dateUpdated": "2026-08-19T16:29:15.060Z"
},
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SVM: Bump asid_generation on CPU online to avoid ASID collision after hotplug\n\nIf a vCPU stays scheduled out (or blocked) while the last pCPU it ran\non goes through a hotplug cycle (online->offline->online), and the vCPU\nthen resumes execution on the same pCPU, then it is possible for it to\nrun with an ASID that has now been assigned to a different vCPU,\nresulting in stale TLB translations being used.\n\nsvm_enable_virtualization_cpu() resets asid_generation to 1 and sets\nnext_asid to max_asid + 1 on every CPU online event, including hotplug\ncycles. Because next_asid starts beyond the pool boundary, the first\ncall to new_asid() after an online event always wraps the pool,\nincrementing asid_generation to 2 and assigning ASIDs starting from\nmin_asid.\n\nConsider two vCPUs from different VMs, vCPU-A pinned to CPU-X holding\nasid_generation=2 and ASID=N from before the hotplug event:\n\n 1. CPU-X goes offline and back online: asid_generation resets to 1,\n next_asid = max_asid + 1.\n\n 2. One or more vCPUs migrate to CPU-X and call new_asid(), wrapping\n the pool and consuming ASIDs starting from min_asid. Eventually\n vCPU-B from a different VM is assigned asid_generation=2, ASID=N\n — the same ASID that vCPU-A held before the hotplug.\n\n 3. vCPU-A enters pre_svm_run() on CPU-X: current_vmcb->cpu is\n unchanged so the migration branch is skipped. Its saved\n asid_generation=2 matches sd->asid_generation=2, so the generation\n check silently passes and vCPU-A continues running with ASID=N —\n the same ASID just freshly assigned to vCPU-B.\n\nBoth vCPUs from different VMs now run on CPU-X with the same ASID,\ncausing them to share NPT TLB entries and producing stale translations.\n\nThe collision manifests as a KVM internal error (Suberror: 1, emulation\nfailure). The NPT page fault reports a faulting GPA far outside the\nVM's physical memory range — a sign of stale TLB translations being\nused. KVM falls back to instruction emulation, which fails on\nFPU/XSave instructions (XRSTOR, STMXCSR) that the emulator does not\nimplement.\n\nFix this by incrementing asid_generation instead of resetting it to 1\nin svm_enable_virtualization_cpu(). On module load, asid_generation\nstarts at 0 (memset) and the increment produces 1, identical to the\nold behaviour. On subsequent hotplug cycles the generation advances\nbeyond any value a vCPU previously observed on this CPU, so the\ngeneration check in pre_svm_run() reliably forces new_asid() on every\nvCPU after every hotplug cycle."
}
],
"affected": [
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"arch/x86/kvm/svm/svm.c"
],
"versions": [
{
"version": "774c47f1d78e373a6bd2964f4e278d1ce26c21cb",
"lessThan": "2028b81321dc757b6875b99c10d908e349c141e2",
"status": "affected",
"versionType": "git"
},
{
"version": "774c47f1d78e373a6bd2964f4e278d1ce26c21cb",
"lessThan": "60283726f2845bd78b95efbd0e50b93944780477",
"status": "affected",
"versionType": "git"
},
{
"version": "774c47f1d78e373a6bd2964f4e278d1ce26c21cb",
"lessThan": "7508916b4b55d6f5ecc68cd09774dabd3a6b4440",
"status": "affected",
"versionType": "git"
},
{
"version": "774c47f1d78e373a6bd2964f4e278d1ce26c21cb",
"lessThan": "0f33b1c457c2199ed130b92cc2ff363a3f7b9415",
"status": "affected",
"versionType": "git"
},
{
"version": "774c47f1d78e373a6bd2964f4e278d1ce26c21cb",
"lessThan": "6b542d116acecb83a1ca34e8eace304cff6a4ec9",
"status": "affected",
"versionType": "git"
},
{
"version": "774c47f1d78e373a6bd2964f4e278d1ce26c21cb",
"lessThan": "25f744ffa0c8e799e06250ce2e618367b166b0d4",
"status": "affected",
"versionType": "git"
}
]
},
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"arch/x86/kvm/svm/svm.c"
],
"versions": [
{
"version": "2.6.21",
"status": "affected"
},
{
"version": "0",
"lessThan": "2.6.21",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.1.183",
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.6.148",
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.12.101",
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "6.18.42",
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "7.1.6",
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"versionType": "semver"
},
{
"version": "7.2",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"operator": "OR",
"negate": false,
"cpeMatch": [
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "2.6.21",
"versionEndExcluding": "6.1.183"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "2.6.21",
"versionEndExcluding": "6.6.148"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "2.6.21",
"versionEndExcluding": "6.12.101"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "2.6.21",
"versionEndExcluding": "6.18.42"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "2.6.21",
"versionEndExcluding": "7.1.6"
},
{
"vulnerable": true,
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "2.6.21",
"versionEndExcluding": "7.2"
}
]
}
]
}
],
"references": [
{
"url": "https://git.kernel.org/stable/c/2028b81321dc757b6875b99c10d908e349c141e2"
},
{
"url": "https://git.kernel.org/stable/c/60283726f2845bd78b95efbd0e50b93944780477"
},
{
"url": "https://git.kernel.org/stable/c/7508916b4b55d6f5ecc68cd09774dabd3a6b4440"
},
{
"url": "https://git.kernel.org/stable/c/0f33b1c457c2199ed130b92cc2ff363a3f7b9415"
},
{
"url": "https://git.kernel.org/stable/c/6b542d116acecb83a1ca34e8eace304cff6a4ec9"
},
{
"url": "https://git.kernel.org/stable/c/25f744ffa0c8e799e06250ce2e618367b166b0d4"
}
],
"title": "KVM: SVM: Bump asid_generation on CPU online to avoid ASID collision after hotplug",
"x_generator": {
"engine": "bippy-1.2.0"
}
},
"adp": [
{
"metrics": [
{
"other": {
"type": "ssvc",
"content": {
"id": "CVE-2026-68093",
"role": "CISA Coordinator",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-11-06T16:42:24.942470Z"
}
}
}
],
"title": "CISA ADP Vulnrichment",
"providerMetadata": {
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP",
"dateUpdated": "2026-11-06T16:44:58.589Z"
}
}
]
}
}