Opera before 9.52 on Windows, Linux, FreeBSD, and Solaris, when processing custom shortcut and menu commands, can produce argument strings that contain uninitialized memory, which might allow user-assisted remote attackers to execute arbitrary code or conduct other attacks via vectors related to activation of a shortcut.
Gentoo Linux Security Advisory GLSA 200811-01 - Multiple vulnerabilities have been discovered in Opera, allowing for the execution of arbitrary code. Versions below 9.62 are affected.