Yahoo! released a critical patch for its chat client, Yahoo! Messenger on August 30th. If you have Yahoo Messenger installed before August 29th, you need to get this patch installed. Here are the details in form of a FAQ at Yahoo's site: Yahoo! ActiveX Control Update. Earlier on August 21st, Yahoo! had released a security update and a plea to the users to upgrade to version 188.8.131.526 that included the security update. If you have not already done, download Yahoo! Messenger now.