Secunia

GreyMagic has discovered a vulnerability in Opera, allowing a malicious website to steal sensitive information and conduct cross-site scripting attacks.

The vulnerability is caused due to universal write access being enabled on the "location" object. This can be exploited by replacing methods in this object making it possible for a malicious website to override cross-site scripting restrictions for any website or local file.

Reportedly, this issue is related to:
SA7991

A weakness was also reported, which can be exploited to determine the presence of files and directories on a user's system.

The vulnerability has been reported in version 7.53 and prior.

Solution
Update to version 7.54.
Further details available in Customer Area

Provided and/or discovered by
GreyMagic

Changelog
Further details available in Customer Area

Original Advisory
http://www.greymagic.com/security/advisories/gm008-op/
http://www.greymagic.com/security/advisories/gm009-op/

Other references
Further details available in Customer Area

Deep Links
Links available in Customer Area