NULL Pointer Dereference Affecting xen package, versions <4.14.1-r0


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.11% (45th percentile)

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  • Snyk IDSNYK-ALPINE316-XEN-2845776
  • published1 Jan 2021
  • disclosed15 Dec 2020

Introduced: 15 Dec 2020

CVE-2020-29571  (opens in a new tab)
CWE-476  (opens in a new tab)

How to fix?

Upgrade Alpine:3.16 xen to version 4.14.1-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream xen package and not the xen package as distributed by Alpine. See How to fix? for Alpine:3.16 relevant fixed versions and status.

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 Scores

version 3.1