CVE-2020-29571

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'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.

How to fix CVE-2020-29571

To remediate CVE-2020-29571, upgrade the affected package to a fixed version below.

• —upgrade to 4.13.2-r3 or later
• —upgrade to 4.14.0+88-g1d1d1f5391-1 or later

Is CVE-2020-29571 being exploited?

Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.

Affected packages (2)

• from 0, < 4.13.2-r3
• from 0, < 4.14.0+88-g1d1d1f5391-1

CVSS scores

References (2)

• ADVISORYsecurity.alpinelinux.org/vuln/CVE-2020-29571
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2020-29571