JustSystems JUST Online Update, as used in Ichitaro through 2014 and other products, does not properly validate signatures of update modules, which allows remote attackers to spoof modules and execute arbitrary code via a crafted signature.

Stack-based buffer overflow in JustSystems Corporation Ichitaro 13, 2004 through 2009, Viewer 2009 19.0.1.0 and earlier, and other versions allows context-dependent attackers to execute arbitrary code via a crafted Rich Text File (RTF), related to "pvpara ffooter."

Unspecified vulnerability in JustSystems Ichitaro 13, 2004 through 2008, Lite2, and Ichitaro viewer 5.1.5.0 and earlier allows remote attackers to execute arbitrary code via a crafted file, as exploited in the wild by Trojan.Tarodrop.H in March 2009.

Buffer overflow in JustSystems JSFC.DLL, as used in multiple JustSystems products such as Ichitaro, allows remote attackers to execute arbitrary code via a crafted .JTD file.

Multiple buffer overflows in the rich text processing functionality in JustSystems Ichitaro 2004 through 2007, 11 through 13, and other versions allow remote attackers to execute arbitrary code via a long (1) pard field or (2) font name in the fcharset0 field, which is not properly handled in (a) JSTARO4.OCX; or (3) a long title, which is not properly handled by (b) TJSVDA.DLL.

Stack-based buffer overflow in Justsystem Ichitaro 9.x through 13.x, Ichitaro 2004, 2005, 2006, and Government 2006; Ichitaro for Linux; and FormLiner before 20060818 allows remote attackers to execute arbitrary code via long Unicode strings in a crafted document, as being actively exploited by malware such as Trojan.Tarodrop. NOTE: some details are obtained from third party information.