Here is a description from (secunia.com) of the specific vulnerability that I appear to have suffered.  It agrees with Frank Niu's info.

Description:
Steve Wiseman has reported a vulnerability in RealVNC, which can be exploited by malicious people to bypass certain security restrictions.

The vulnerability is caused due to an error within the handling of VNC password authentication requests. This can be exploited to bypass authentication and allows access to the remote system without requiring knowledge of the VNC password.

The vulnerability has been reported in version 4.1.1. Other versions may also be affected.

Note: Version 4.0 is reportedly not affected.

Solution:
Update to Free Edition version 4.1.2 or Personal Edition/Enterprise Edition version 4.2.3.

Carey
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist