CVE-2020-11743

Description

An issue was discovered in Xen through 4.13.x, allowing guest OS users to cause a denial of service because of a bad error path in GNTTABOP_map_grant. Grant table operations are expected to return 0 for success, and a negative number for errors. Some misplaced brackets cause one error path to return 1 instead of a negative value. The grant table code in Linux treats this condition as success, and proceeds with incorrectly initialised state. A buggy or malicious guest can construct its grant table in such a way that, when a backend domain tries to map a grant, it hits the incorrect error path. This will crash a Linux based dom0 or backend domain.

How to fix CVE-2020-11743

To remediate CVE-2020-11743, upgrade the affected package to a fixed version below.

• —upgrade to 4.12.2-r1 or later
• —upgrade to 4.11.4-1 or later

Is CVE-2020-11743 being exploited?

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

Affected packages (2)

• from 0, < 4.12.2-r1
• from 0, < 4.11.4-1

CVSS scores

References (2)

• ADVISORYsecurity.alpinelinux.org/vuln/CVE-2020-11743
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2020-11743