It was discovered that libXdmcp before 1.1.2 including used weak entropy to generate session keys. On a multi-user system using xdmcp, a local attacker could potentially use information available from the process list to brute force the key, allowing them to hijack other users' sessions.
http://www.securityfocus.com/bid/96480
http://www.securitytracker.com/id/1037919
https://access.redhat.com/errata/RHSA-2017:1865
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2017-2625
https://cgit.freedesktop.org/xorg/lib/libXdmcp/commit/?id=0554324ec6bbc2071f5d1f8ad211a1643e29eb1f
Source: MITRE
Published: 2018-07-27
Updated: 2019-10-09
Type: CWE-320
Base Score: 2.1
Vector: AV:L/AC:L/Au:N/C:P/I:N/A:N
Impact Score: 2.9
Exploitability Score: 3.9
Severity: LOW
Base Score: 5.5
Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Impact Score: 3.6
Exploitability Score: 1.8
Severity: MEDIUM