WinSig.exe in eSignal 10.6.2425 and earlier allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via (1) a long StyleTemplate element in a QUO, SUM or POR file, which triggers a stack-based buffer overflow, or (2) a long Font->FaceName field (aka FaceName element), which triggers a heap-based buffer overflow.  NOTE: some of these details are obtained from third party information.