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.
Severity
CVSS 3.0
5.5 medium
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
EPSS
0.5% chance of exploitation in the next 30 days; higher than 45% of CVEs (scores of 2026-10-31)