UnrealIRCd 3.2.8.1, as distributed on certain mirror sites from November 2009 through June 2010, contains an externally introduced modification (Trojan Horse) in the DEBUG3_DOLOG_SYSTEM macro, which allows remote attackers to execute arbitrary commands.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.722
EPSS Ranking 98.7%