The ByteCode Verifier component of Microsoft Virtual Machine (VM) build 5.0.3809 and earlier, as used in Windows and Internet Explorer, allows remote attackers to bypass security checks and execute arbitrary code via a malicious Java applet, aka "Flaw in Microsoft VM Could Enable System Compromise."

A certain class that supports XML (Extensible Markup Language) in Microsoft Virtual Machine (VM) 5.0.3805 and earlier, probably com.ms.osp.ospmrshl, exposes certain unsafe methods, which allows remote attackers to execute unsafe code via a Java applet, aka "Inappropriate Methods Exposed in XML Support Classes."

Java Database Connectivity (JDBC) classes in Microsoft Virtual Machine (VM) up to and including 5.0.3805 allow remote attackers to load and execute DLLs (dynamic link libraries) via a Java applet that calls the constructor for com.ms.jdbc.odbc.JdbcOdbc with the desired DLL terminated by a null string, aka "DLL Execution via JDBC Classes."

Microsoft Virtual Machine (VM) up to and including build 5.0.3805 allows remote attackers to cause a denial of service (crash) in Internet Explorer via invalid handle data in a Java applet, aka "Handle Validation Flaw."

Java Runtime Environment (JRE) Bytecode Verifier allows remote attackers to escape the Java sandbox and execute commands via an applet containing an illegal cast operation, as seen in (1) Microsoft VM build 3802 and earlier as used in Internet Explorer 4.x and 5.x, (2) Netscape 6.2.1 and earlier, and possibly other implementations that use vulnerable versions of SDK or JDK, aka a variant of the "Virtual Machine Verifier" vulnerability.

Vulnerability in Java Runtime Environment (JRE) allows remote malicious web sites to hijack or sniff a web client's sessions, when an HTTP proxy is being used, via a Java applet that redirects the session to another server, as seen in (1) Netscape 6.0 through 6.1 and 4.79 and earlier, (2) Microsoft VM build 3802 and earlier as used in Internet Explorer 4.x and 5.x, and possibly other implementations that use vulnerable versions of SDK or JDK.