In Xymon through 4.3.28, a stack-based buffer overflow vulnerability exists in the history viewer component via a long hostname or service parameter to history.c.
Exploitability
AV:NAC:LPR:NUI:NScope
S:UImpact
C:HI:HA:H9.8/CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H