Secunia

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.
Further details available in Customer Area

Provided and/or discovered by
Steve Wiseman

Changelog
Further details available in Customer Area

Original Advisory
RealVNC:
http://www.realvnc.com/products/free/4.1/release-notes.html
http://www.realvnc.com/products/personal/4.2/release-notes.html
http://www.realvnc.com/products/enterprise/4.2/release-notes.html

IntelliAdmin:
http://www.intelliadmin.com/blog/2006/05/security-flaw-in-realvnc-411.html
http://www.intelliadmin.com/blog/2006/05/vnc-flaw-proof-of-concept.html

Other references
Further details available in Customer Area

Deep Links
Links available in Customer Area