{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-79611",
        "assignerOrgId": "23aa2041-22e1-471f-9209-9b7396fa234f",
        "state": "PUBLISHED",
        "assignerShortName": "XEN",
        "dateReserved": "2026-08-25T07:35:05.290Z",
        "datePublished": "2026-10-13T15:44:56.361Z",
        "dateUpdated": "2026-10-20T17:31:41.971Z"
    },
    "containers": {
        "cna": {
            "title": "VMX: VMentry failure with branch tracing and blocked states",
            "datePublic": "2026-10-13T12:00:00.000Z",
            "descriptions": [
                {
                    "lang": "en",
                    "value": "For XSA-308 logic was introduced, as VMX VMEntry checks do not like the\nexact combination of state which occurs when #DB in intercepted, Single\nStepping is active, and blocked by STI/MovSS is active, despite this being\na legitimate state to be in.  The resulting VMEntry failure is fatal to\nthe guest.\n\nSadly there is another special sub-case of the above, with branch tracing\nenabled.  In that case the prior adjustment would still cause a VMentry\nfailure, as before fatal to the guest."
                }
            ],
            "impacts": [
                {
                    "descriptions": [
                        {
                            "lang": "en",
                            "value": "HVM/PVH guest userspace code may be able to crash the guest, resulting\nin a guest Denial of Service."
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "defaultStatus": "unknown",
                    "product": "Xen",
                    "vendor": "Xen",
                    "versions": [
                        {
                            "status": "unknown",
                            "version": "consult Xen advisory XSA-518"
                        }
                    ]
                }
            ],
            "configurations": [
                {
                    "lang": "en",
                    "value": "All versions of Xen are affected.\n\nOnly systems supporting VMX hardware virtual extensions (Intel, VIA or\nZhaoxin CPUs) are affected.  Arm as well as AMD and Hygon systems are\nunaffected.\n\nOnly HVM/PVH guests are affected.  PV guests cannot leverage the\nvulnerability."
                }
            ],
            "workarounds": [
                {
                    "lang": "en",
                    "value": "Running only PV guests will avoid this vulnerability.\n\nRunning HVM guests on only AMD or Hygon hardware will also avoid this\nvulnerability."
                }
            ],
            "credits": [
                {
                    "lang": "en",
                    "type": "finder",
                    "value": "This issue was discovered by Claude Opus and diagnosed as a security issue\nby Teddy Astie of Vates."
                }
            ],
            "references": [
                {
                    "url": "https://xenbits.xenproject.org/xsa/advisory-518.html"
                }
            ],
            "providerMetadata": {
                "orgId": "23aa2041-22e1-471f-9209-9b7396fa234f",
                "shortName": "XEN",
                "dateUpdated": "2026-10-13T15:44:56.361Z"
            }
        },
        "adp": [
            {
                "title": "CVE Program Container",
                "references": [
                    {
                        "url": "http://xenbits.xen.org/xsa/advisory-518.html"
                    },
                    {
                        "url": "http://www.openwall.com/lists/oss-security/2026/10/13/7"
                    }
                ],
                "providerMetadata": {
                    "orgId": "af854a3a-2127-422b-91ae-364da2661108",
                    "shortName": "CVE",
                    "dateUpdated": "2026-10-13T16:13:51.786Z"
                }
            },
            {
                "problemTypes": [
                    {
                        "descriptions": [
                            {
                                "type": "CWE",
                                "cweId": "CWE-843",
                                "lang": "en",
                                "description": "CWE-843 Access of Resource Using Incompatible Type ('Type Confusion')"
                            }
                        ]
                    }
                ],
                "metrics": [
                    {
                        "cvssV3_1": {
                            "scope": "UNCHANGED",
                            "version": "3.1",
                            "baseScore": 5.5,
                            "attackVector": "LOCAL",
                            "baseSeverity": "MEDIUM",
                            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
                            "integrityImpact": "NONE",
                            "userInteraction": "NONE",
                            "attackComplexity": "LOW",
                            "availabilityImpact": "HIGH",
                            "privilegesRequired": "LOW",
                            "confidentialityImpact": "NONE"
                        }
                    },
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-10-20T17:31:36.841344Z",
                                "id": "CVE-2026-79611",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "Technical Impact": "partial"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-10-20T17:31:41.971Z"
                }
            }
        ]
    }
}