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CVE-2026-74516

Estado: RecibidaAlta (8.2)—

In the Linux kernel, the following vulnerability has been resolved:

KVM: SVM: Update x2APIC MSR intercepts if AVIC is inhibited while L2 is active

Always update x2APIC MSR intercepts for L1 when AVIC is deactivated, even if L2 is active and KVM is using a separate MSR bitmap to run L2. If AVIC is fully enabled prior to running L2, and is then inhibited while L2 is active (for a VM-scoped inhibit), then KVM will run L1 with AVIC disabled, but with x2APIC MSR intercepts disabled, i.e. will allow L1 to read most of the host's APIC state, send arbitrary interrupts, change task priority, and ultimately trivially DoS the host.

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E.g. sending a self-IPI in L1 on HYPERV_REENLIGHTENMENT_VECTOR, 0xee, with CONFIG_HYPERV=n in the host kernel as a "safe" PoC, yields:

And hacking KVM to abuse kvm_set_posted_intr_wakeup_handler() to register a handler and WARN on POSTED_INTR_WAKEUP_VECTOR yields:

Detalles técnicos trazas, registros y código del informe original
  Spurious interrupt (vector 0xee) on CPU#425. Acked

  ------------[ cut here ]------------
  WARNING: arch/x86/kvm/svm/svm.c:5594 at pi_wakeup_handler+0x9/0x10 [kvm_amd], CPU#156: nested_x2apic_t/316940
  CPU: 156 UID: 0 PID: 316940 Comm: nested_x2apic_t Tainted: G S   U
  Tainted: [S]=CPU_OUT_OF_SPEC, [U]=USER
  Hardware name: Google Astoria-Turin/astoria, BIOS 0.20260209.0-0 02/09/2026
  RIP: 0010:pi_wakeup_handler+0x9/0x10 [kvm_amd]
  Call Trace:
   <IRQ>
   sysvec_kvm_posted_intr_wakeup_ipi+0x64/0x80
   </IRQ>
   <TASK>
   asm_sysvec_kvm_posted_intr_wakeup_ipi+0x1a/0x20
  RIP: 0010:vcpu_run+0x1430/0x1e40 [kvm]
   kvm_arch_vcpu_ioctl_run+0x2c1/0x600 [kvm]
   kvm_vcpu_ioctl+0x580/0x6b0 [kvm]
   __se_sys_ioctl+0x6d/0xb0
   do_syscall_64+0x10a/0x480
   entry_SYSCALL_64_after_hwframe+0x4b/0x53
  RIP: 0033:0x46ff4b
   </TASK>
  ---[ end trace 0000000000000000 ]---

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Inferido por reglas deterministas a partir del vector CVSS y la CWE. Solo orientativo.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Threat Intelligence ProgramExecution PreventionApplication Isolation and SandboxingExploit ProtectionUpdate Software

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Linux — Linux KernelAI

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-74516",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 8.2,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "HIGH",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 6,
        "exploitabilityScore": 1.5
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "091abbf578f926e763adc0f577baeb7f405b4bdc",
              "lessThan": "4ca05385b3ddbd463be17c6d69ec76fca657081d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "091abbf578f926e763adc0f577baeb7f405b4bdc",
              "lessThan": "6664a5aea45318f4ec156a729949b474dd6e3159",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "091abbf578f926e763adc0f577baeb7f405b4bdc",
              "lessThan": "f12373625b4dc9bcc89c41872648878c73bb9272",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "091abbf578f926e763adc0f577baeb7f405b4bdc",
              "lessThan": "7668c58dcf465559dc7a0d2e95e9cb79cf47454b",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "091abbf578f926e763adc0f577baeb7f405b4bdc",
              "lessThan": "89f9e8398e79c49886766fc24a84c37726231104",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "091abbf578f926e763adc0f577baeb7f405b4bdc",
              "lessThan": "7d3aae206663c4e006b25a1c7a20a4029e67da76",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "arch/x86/kvm/svm/avic.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.0"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "6.0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "6.1.183",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.151",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.103",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.44",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.1.8",
              "versionType": "semver",
              "lessThanOrEqual": "7.1.*"
            },
            {
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "arch/x86/kvm/svm/avic.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-08-15T13:17:56.737",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/4ca05385b3ddbd463be17c6d69ec76fca657081d",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/6664a5aea45318f4ec156a729949b474dd6e3159",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7668c58dcf465559dc7a0d2e95e9cb79cf47454b",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7d3aae206663c4e006b25a1c7a20a4029e67da76",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/89f9e8398e79c49886766fc24a84c37726231104",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/f12373625b4dc9bcc89c41872648878c73bb9272",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SVM: Update x2APIC MSR intercepts if AVIC is inhibited while L2 is active\n\nAlways update x2APIC MSR intercepts for L1 when AVIC is deactivated, even\nif L2 is active and KVM is using a separate MSR bitmap to run L2.  If AVIC\nis fully enabled prior to running L2, and is then inhibited while L2 is\nactive (for a VM-scoped inhibit), then KVM will run L1 with AVIC disabled,\nbut with x2APIC MSR intercepts disabled, i.e. will allow L1 to read most of\nthe host's APIC state, send arbitrary interrupts, change task priority, and\nultimately trivially DoS the host.\n\nE.g. sending a self-IPI in L1 on HYPERV_REENLIGHTENMENT_VECTOR, 0xee, with\nCONFIG_HYPERV=n in the host kernel as a \"safe\" PoC, yields:\n\n  Spurious interrupt (vector 0xee) on CPU#425. Acked\n\nAnd hacking KVM to abuse kvm_set_posted_intr_wakeup_handler() to register a\nhandler and WARN on POSTED_INTR_WAKEUP_VECTOR yields:\n\n  ------------[ cut here ]------------\n  WARNING: arch/x86/kvm/svm/svm.c:5594 at pi_wakeup_handler+0x9/0x10 [kvm_amd], CPU#156: nested_x2apic_t/316940\n  CPU: 156 UID: 0 PID: 316940 Comm: nested_x2apic_t Tainted: G S   U\n  Tainted: [S]=CPU_OUT_OF_SPEC, [U]=USER\n  Hardware name: Google Astoria-Turin/astoria, BIOS 0.20260209.0-0 02/09/2026\n  RIP: 0010:pi_wakeup_handler+0x9/0x10 [kvm_amd]\n  Call Trace:\n   <IRQ>\n   sysvec_kvm_posted_intr_wakeup_ipi+0x64/0x80\n   </IRQ>\n   <TASK>\n   asm_sysvec_kvm_posted_intr_wakeup_ipi+0x1a/0x20\n  RIP: 0010:vcpu_run+0x1430/0x1e40 [kvm]\n   kvm_arch_vcpu_ioctl_run+0x2c1/0x600 [kvm]\n   kvm_vcpu_ioctl+0x580/0x6b0 [kvm]\n   __se_sys_ioctl+0x6d/0xb0\n   do_syscall_64+0x10a/0x480\n   entry_SYSCALL_64_after_hwframe+0x4b/0x53\n  RIP: 0033:0x46ff4b\n   </TASK>\n  ---[ end trace 0000000000000000 ]---"
    }
  ],
  "lastModified": "2026-08-19T17:21:08.400",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}