CERT has issued an advisory and Microsoft has updated their advisory regarding long URL strings that can a buffer overflow condition. The August 22nd release was postponed, so that QA issues could be fully resolved.
CERT - Microsoft Internet Explorer long URL buffer overflow
http://www.kb.cert.org/vuls/id/821156
QUOTE: Microsoft Internet Explorer 6 Service Pack 1 on Windows 2000 and Windows XP SP1 contains a vulnerability when viewing a web site using the HTTP 1.1 protocol. If the web site uses HTTP 1.1 compression and contains an overly long URL, a buffer overflow can occur. Note that this vulnerability was introduced with the first release of the MS06-042 updates on August 8, 2006.
MS06-042 Re-release postponed to ensure Quality
http://blogs.technet.com/msrc/archive/2006/08/22/448689.aspx
QUOTE: On August 15, 2006 Microsoft announced that it would be re-releasing MS06-042 Tuesday, August 22, 2006 to address an issue affecting Internet Explorer 6 Service Pack 1 customers discussed in Microsoft Knowledge Base Article 923762. Due to an issue discovered in final testing, Microsoft will not be re-releasing MS06-042 today. This update will be re-released for Internet Explorer 6 Service Pack 1 when it meets an appropriate level of quality for broad distribution.
Additional Links:
Microsoft Security Advisory (923762)
http://www.microsoft.com/technet/security/advisory/923762.mspx
Secunia
http://secunia.com/advisories/21557/
FrSIRT
http://www.frsirt.com/english/advisories/2006/3356
Security Focus
http://www.securityfocus.com/news/11408