CVE-2020-11743: Medium severity XEN Xen vulnerability
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 GNTTABOPmapgrant. 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 Software
Remediation
Patch Available
Event History
Frequently Asked Questions
What is CVE-2020-11743?
CVE-2020-11743 is a vulnerability in Xen that allows guest OS users to cause a denial of service.
How does CVE-2020-11743 cause a denial of service?
CVE-2020-11743 causes a denial of service due to a bad error path in GNTTABOP_map_grant, which can be triggered by guest OS users.
Which versions of Xen are affected by CVE-2020-11743?
Xen versions up to and including 4.13.x are affected by CVE-2020-11743.
How can I fix CVE-2020-11743?
To fix CVE-2020-11743, update Xen to version 4.11.3+24- or later, depending on your operating system.
Where can I find more information about CVE-2020-11743?
You can find more information about CVE-2020-11743 at the following references: [Xen Advisory 316](http://xenbits.xen.org/xsa/advisory-316.html), [Xen Advisory 316](https://xenbits.xen.org/xsa/advisory-316.html), [Openwall](http://www.openwall.com/lists/oss-security/2020/04/14/3).