dunno details, but there's a link from the register article.
bumped 7.21 stable, affected versions are <=7.20
There is another security bug in 7.21, marked 7.22 stable
From the changelog:
* Security update specifically addressing the downloading of setup files in Opera (bug reported by S.G. Masood)
*** Bug 33334 has been marked as a duplicate of this bug. ***
opera-7.23 is in portage.
changing resolution to FIXED