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CVE-2021-3308

Status: ModifiedMedium (5.5)—

An issue was discovered in Xen 4.12.3 through 4.12.4 and 4.13.1 through 4.14.x. An x86 HVM guest with PCI pass through devices can force the allocation of all IDT vectors on the system by rebooting itself with MSI or MSI-X capabilities enabled and entries setup. Such reboots will leak any vectors used by the MSI(-X) entries that the guest might had enabled, and hence will lead to vector exhaustion on the system, not allowing further PCI pass through devices to work properly. HVM guests with PCI pass through devices can mount a Denial of Service (DoS) attack affecting the pass through of PCI devices to other guests or the hardware domain. In the latter case, this would affect the entire host.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (2)

Fedoraproject — FedoraXEN — XEN

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2021-3308",
  "cveTags": [],
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          "vectorString": "AV:L/AC:L/Au:N/C:N/I:N/A:C",
          "authentication": "NONE",
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          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
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  "published": "2021-01-26T20:15:12.303",
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      "lang": "en",
      "value": "An issue was discovered in Xen 4.12.3 through 4.12.4 and 4.13.1 through 4.14.x. An x86 HVM guest with PCI pass through devices can force the allocation of all IDT vectors on the system by rebooting itself with MSI or MSI-X capabilities enabled and entries setup. Such reboots will leak any vectors used by the MSI(-X) entries that the guest might had enabled, and hence will lead to vector exhaustion on the system, not allowing further PCI pass through devices to work properly. HVM guests with PCI pass through devices can mount a Denial of Service (DoS) attack affecting the pass through of PCI devices to other guests or the hardware domain. In the latter case, this would affect the entire host."
    },
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      "value": "Se detectó un problema en Xen versiones 4.12.3 hasta 4.12.4 y versiones 4.13.1 hasta 4.14.x. Un invitado HVM x86 con PCI pasando a través de los dispositivos puede forzar la asignación de todos los vectores IDT en el sistema al reiniciarse con las capacidades MSI o MSI-X habilitadas y la configuración de entradas. Dichos reinicios filtrarán todos los vectores usados por las entradas MSI(-X) que el invitado podría haber habilitado y, por lo tanto, conllevarán al agotamiento del vector en el sistema, lo que no permitirá que otros dispositivos PCI pasen a funcionar correctamente. Los invitados HVM con PCI pasando a través de los dispositivos pueden montar un ataque de denegación de servicio (DoS) que afecta el paso de dispositivos PCI para otros invitados o al dominio del hardware. En el último caso, esto afectaría a todo el host"
    }
  ],
  "lastModified": "2026-06-17T04:04:54.850",
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