{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-64172",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2026-07-19T07:54:57.039Z",
        "datePublished": "2026-07-19T15:40:57.153Z",
        "dateUpdated": "2026-08-05T12:39:52.348Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-08-05T12:39:52.348Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SVM: Disable AVIC IPI virtualization on Hygon Family 18h (erratum #1235)\n\nHygon Family 18h CPUs are derived from AMD Family 17h (Zen1) silicon and\nshare the same erratum #1235: hardware may read a stale IsRunning=1 bit\nduring ICR write emulation and silently fail to generate an\nAVIC_IPI_FAILURE_TARGET_NOT_RUNNING VM-Exit on the sending vCPU.\n\nThe absence of the VM-Exit causes KVM to miss the required wakeup of\nblocking target vCPUs, leading to hung vCPUs and unbounded delays in\nguest execution.\n\nExtend the existing AMD Family 17h erratum #1235 workaround to also cover\nHygon Family 18h.  With IPI virtualization disabled, KVM never sets\nIsRunning=1 in the Physical ID table, so every non-self IPI generates a\nVM-Exit and is correctly emulated."
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "version": "3.1",
                        "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H",
                        "baseScore": 7.1,
                        "baseSeverity": "HIGH"
                    },
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "AV:L - Exploitation requires executing guest code that issues APIC ICR writes against blocking vCPUs; the vulnerable KVM/AVIC path is reached from within a VM, not from remote network packets to the host.\nAC:L - The erratum is a race on IsRunning that the attacker fully controls by pinning one vCPU in a blocking halt/mwait state and having another vCPU send timed IPIs; no conditions outside attacker influence are required once AVIC is active.\nPR:N - No host privileges are needed beyond the ability to run code in a tenant VM on a Hygon KVM host; a cloud customer with a standard VM instance can trigger the bug without host root or special capabilities.\nUI:N - No victim interaction is required; a malicious guest can autonomously orchestrate blocking and IPI traffic to hang vCPUs.\nS:C - In nested virtualization deployments, a malicious L1 hypervisor guest can cause hung vCPUs and unbounded execution delays in L2 guests via the host KVM AVIC path, crossing the L1/L2 security boundary even though there is no host escape.\nC:N - The bug is a missed VM-exit and missed vCPU wakeup with no out-of-bounds access, use-after-free, or information disclosure primitive.\nI:N - No memory or data structures are corrupted; the failure only prevents delivery of required wake events to blocking vCPUs.\nA:H - Missed wakeups cause hung vCPUs and unbounded delays in guest execution, constituting a reliable denial-of-service against VM availability."
                        }
                    ]
                }
            ],
            "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/avic.c"
                    ],
                    "versions": [
                        {
                            "version": "8de4a1c8164e5b2e40d1df764840a31de983f40b",
                            "lessThan": "94ade38f317ea086a181db0e6b69c574b3b70a5e",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "8de4a1c8164e5b2e40d1df764840a31de983f40b",
                            "lessThan": "9560e6fee887a9594a89fa265b5b9c79b1591803",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "8de4a1c8164e5b2e40d1df764840a31de983f40b",
                            "lessThan": "9a12fa5213cfc391e0eed63902d3be98f0913765",
                            "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/avic.c"
                    ],
                    "versions": [
                        {
                            "version": "6.17",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "6.17",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.34",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.0.11",
                            "lessThanOrEqual": "7.0.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.1",
                            "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": "6.17",
                                    "versionEndExcluding": "6.18.34"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.17",
                                    "versionEndExcluding": "7.0.11"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.17",
                                    "versionEndExcluding": "7.1"
                                }
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            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/94ade38f317ea086a181db0e6b69c574b3b70a5e"
                },
                {
                    "url": "https://git.kernel.org/stable/c/9560e6fee887a9594a89fa265b5b9c79b1591803"
                },
                {
                    "url": "https://git.kernel.org/stable/c/9a12fa5213cfc391e0eed63902d3be98f0913765"
                }
            ],
            "title": "KVM: SVM: Disable AVIC IPI virtualization on Hygon Family 18h (erratum #1235)",
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