Remote vulnerabilities for two graphical user environments have been announced, four for an environment which has been around since the beginning of distributed computing, and one with a newer contender.

iDefense have released four vulnerabilities for various vendor implementations of the popular X11 implementations. 

Multiple Vendor X Server XInput Extension Multiple Memory Corruption Vulnerabilities (CVE-2007-6427)
Multiple Vendor X Server TOG-CUP Extension Information Disclosure Vulnerability (CVE-2007-6428)
Multiple Vendor X Server EVI and MIT-SHM Extensions Integer Overflow Vulnerabilities (CVE-2007-6429)
Multiple Vendor X Server XFree86-Misc Extension Invalid Array Index Vulnerability (CVE-2007-5760)

ZDI have released the following remotely exploitable vulnerability for the following products:

• Metaframe Presentation Server 3.0
• Presentation Server 4.0, 4.5
• Access Essentials 1.0, 1.5, 2.0
• Desktop Server 1.0

This vulnerability does not require previous authentication for Citrix.

Citrix Presentation Server IMA Service Heap Overflow Vulnerability (ZDI-08-002)