CVE-2020-29571

Severity CVSS v4.0:

Pending analysis

Type:

CWE-476 NULL Pointer Dereference

Publication date:

15/12/2020

Last modified:

07/11/2023

Description

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&#39;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.

Impact

Vector 3.x

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS v3.1 Severity and Metrics:

Base Score: 6.20 MEDIUM
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector (AV): Local
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): None
Availability (A): High

Base Score 3.x

6.20

Severity 3.x

MEDIUM

Vector 2.0

AV:L/AC:L/Au:N/C:N/I:N/A:C CVSS v2.0 Severity and Metrics:

Base Score: 4.90 MEDIUM
Vector: AV:L/AC:L/Au:N/C:N/I:N/A:C

Attack Vector (AV): Local
Attack Complexity (AC): Low
Authentication (Au): None
Confidentiality (C): None
Integrity (I): None
Availability (A): Complete

Base Score 2.0

4.90

Severity 2.0

MEDIUM

Vulnerable products and versions

CPE	From	Up to
cpe:2.3:o:xen:xen:::::::arm:*	4.4.0 (including)	4.14.0 (including)
cpe:2.3:o:debian:debian_linux:10.0:::::::*
cpe:2.3:o:fedoraproject:fedora:32:::::::*
cpe:2.3:o:fedoraproject:fedora:33:::::::*

To consult the complete list of CPE names with products and versions, see this page

CVE-2020-29571

Description

Impact

Vulnerable products and versions

References to Advisories, Solutions, and Tools