Format string vulnerability in (1) Bahamut IRCd 1.4.35 and earlier, and other IRC daemons based on Bahamut including (2) digatech 1.2.1, (3) methane 0.1.1, (4) AndromedeIRCd 1.2.3-Release, and (5) ircd-RU, when running in debug mode, allows remote attackers to cause a denial of service and possibly execute arbitrary code via a request containing format strings.