The update, which affects Adobe Reader/Acrobat 9.3.2 (and earlier versions), includes a fix for the outstanding PDF "/Launch" functionality social engineering attack vector that was disclosed by researcher Didier Stevens.
As previously reported, Didier created a proof-of-concept PDF file that executes an embedded executable without exploiting any security vulnerabilities.
According to Adobe, the newest version includes changes to resolve the misuse of this command.
We added functionality to block any attempts to launch an executable or other harmful objects by default. We also altered the way the existing warning dialog works to thwart the known social engineering attacks.
This Adobe Reader/Acrobat patch batch was originally scheduled for July 13, 2010.
More information on vulnerabilities fixed in the latest update, see this Adobe advisory.