Opera 12.13 -- High Security Update

[Corrine]

Advisory: DOM events manipulation might be used to execute arbitrary code - Opera Knowledge Base:

Severity: High

Description:

Particular DOM event manipulations can cause Opera to crash. In some cases, this crash might occur in a way that allows execution of arbitrary code. To inject code, additional techniques would have to be employed.
Opera's response:

Opera Software has released Opera 12.13, where this issue has been fixed.

Also of interest is Serious security holes fixed in Opera – but Mac App Store users left at risk again | Naked Security