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CVE-2020-29571

Status: ModifiedMedium (6.2)—

An issue was discovered in Xen through 4.14.x. A bounds check common to most operation time functions specific to FIFO event channels depends on the CPU observing consistent state. While the producer side uses appropriately ordered writes, the consumer side isn't protected against re-ordered reads, and may hence end up de-referencing a NULL pointer. Malicious or buggy guest kernels can mount a Denial of Service (DoS) attack affecting the entire system. Only Arm systems may be vulnerable. Whether a system is vulnerable depends on the specific CPU. x86 systems are not vulnerable.

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 (3)

Debian — Debian LinuxFedoraproject — FedoraXEN — XEN

CWEs

References

Raw JSON (NVD)

Show
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  "id": "CVE-2020-29571",
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          "vectorString": "AV:L/AC:L/Au:N/C:N/I:N/A:C",
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      "value": "An issue was discovered in Xen through 4.14.x. A bounds check common to most operation time functions specific to FIFO event channels depends on the CPU observing consistent state. While the producer side uses appropriately ordered writes, the consumer side isn't protected against re-ordered reads, and may hence end up de-referencing a NULL pointer. Malicious or buggy guest kernels can mount a Denial of Service (DoS) attack affecting the entire system. Only Arm systems may be vulnerable. Whether a system is vulnerable depends on the specific CPU. x86 systems are not vulnerable."
    },
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      "lang": "es",
      "value": "Se detectó un problema en Xen versiones hasta 4.14.x. Una comprobación  de límites común a la mayoría de las funciones de tiempo de operación específicas de los canales de eventos FIFO depende de que la CPU observe un estado consistente. Si bien el lado del productor usa escrituras ordenadas apropiadamente, el lado del consumidor no está protegido contra las lecturas reordenadas y, por lo tanto, puede terminar desreferenciando un puntero NULL. Los kernels invitados maliciosos o con errores pueden montar un ataque de Denegación de Servicio (DoS) que afecte a todo el System. Solo los sistemas Arm pueden ser vulnerables. La vulnerabilidad de un System depende de la CPU específica. Los Sistemas x86 no son vulnerables"
    }
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  "lastModified": "2026-06-17T03:11:27.290",
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