Opera has released a "highly critical" update to plug a nasty code execution hole affecting Windows users.
The vulnerability, confirmed in all Opera versions prior to 9.21 for Windows, is caused due to an error in the handling of torrent files, according to an advisory issued by the Norwegian software company.
The flaw can be exploited to cause a buffer overflow when a user right-clicks a malicious torrent entry in the transfer manager.
"Successful exploitation allows execution of arbitrary code," Opera warned, urging all Windows users to immediately update to version 9.21.
Secunia rates the bug as "highly critical" but notes that simply clicking on the dirty torrent link will not trigger the vulnerability.