An X server's access control is disabled (e.g. through an "xhost +" command) and allows anyone to connect to the server.
http://www.kb.cert.org/vuls/id/704969
Source: Mitre, NVD
Published: 1997-07-01
Updated: 2008-09-09
Base Score: 10
Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C
Severity: Critical
Base Score: 9.8
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H