The default configuration of ASP.NET in Mono before 2.6.4 has a value of FALSE for the EnableViewStateMac property, which allows remote attackers to conduct cross-site scripting (XSS) attacks, as demonstrated by the VIEWSTATE parameter to 2.0/menu/menu1.aspx in the XSP sample project.
Buffer overflow in the Mono.Math.BigInteger class in Mono 1.2.5.1 and earlier allows context-dependent attackers to execute arbitrary code via unspecified vectors related to Reduce in Montgomery-based Pow methods.
Untrusted search path vulnerability in metadata/loader.c in Mono 2.8 and earlier allows local users to gain privileges via a Trojan horse shared library in the current working directory.