CVE-2020-29571

Severity Score

6.2

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

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.

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

*Credits: N/A

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Attack Vector

Local

Attack Complexity

Low

Authentication

None

Confidentiality

None

Integrity

None

Availability

Complete

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2020-12-04 CVE Reserved
2020-12-15 CVE Published
2023-11-08 EPSS Updated
2024-08-04 CVE Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-476: NULL Pointer Dereference

CAPEC

References (5)

URL	Tag	Source

URL	Date	SRC

URL	Date	SRC
https://xenbits.xenproject.org/xsa/advisory-359.html	2023-11-07

URL	Date	SRC
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2C6M6S3CIMEBACH6O7V4H2VDANMO6TVA	2023-11-07
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OBLV6L6Q24PPQ2CRFXDX4Q76KU776GKI	2023-11-07
https://security.gentoo.org/glsa/202107-30	2023-11-07
https://www.debian.org/security/2020/dsa-4812	2023-11-07

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Xen Search vendor "Xen"		Xen Search vendor "Xen" for product "Xen"				>= 4.4.0 <= 4.14.0 Search vendor "Xen" for product "Xen" and version " >= 4.4.0 <= 4.14.0"		arm		Affected
Debian Search vendor "Debian"		Debian Linux Search vendor "Debian" for product "Debian Linux"				10.0 Search vendor "Debian" for product "Debian Linux" and version "10.0"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				32 Search vendor "Fedoraproject" for product "Fedora" and version "32"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				33 Search vendor "Fedoraproject" for product "Fedora" and version "33"		-		Affected