CVE-2020-11743: Fedoraproject Fedora

Medium severity, CVSS 5.5. EPSS: 0.5% chance of exploitation in the next 30 days.

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.

Affected products

• Fedoraproject Fedora: version 32 only
• Xen Xen: up to and including 4.13.0; version 4.13.0 only

Published 2020-04-14. Last modified 2026-06-17.