Adobe Reader 8 contains an input validation error in a JavaScript method. According to Adobe these flaws could result in arbitrary code execution with the permissions of the user running Adobe Reader.
Public now via upstream security bulletin: http://www.adobe.com/support/security/bulletins/apsb08-19.html
This issue was addressed in: Red Hat Enterprise Linux Extras: http://rhn.redhat.com/errata/RHSA-2008-0974.html