Dec 17, 2010 16:08 GMT  ·  By

The newly released Opera 11 brings a lot of enhancements and bug fixes, but also addresses several vulnerabilities that carry a high severity rating.

The new iteration of the Norwegian browser features a long-awaited extensions API and a new tab management model dubbed "stacking."

On the security side, Opera 11 fixes at least four weaknesses, but some of them have not yet been described.

Developers reveal that several high severity issues were fixed and note that "details will be disclosed at a later date."

This is probably a measure to ensure that a large number of users are protected before the vulnerabilities are made public, although the company is not in the habit of holding back information like this.

One of the two vulnerabilities that were documented, carries a moderate severity rating and concerns a rendering problem with security or download dialogs, which can overlap with content from Web pages.

"In some cases, webpage content will be incorrectly displayed on top of the dialogs, or over parts of the dialogs. This content can then display misleading security information, which may be used to convince a user to trust a malicious download, or to to disclose sensitive information," the Opera developers warn.

The second flaw is a low risk one and stems from a failure to clear form input data gathered on WAP pages. This can result in sensitive data leaking to other websites because the browser automatically completes fields with the same name if they exist on the new page.

Clearing this data should normally be performed by the browser when users manually type a new address. However, when they navigate away by clicking on links, the task of clearing the form variables falls on the WAP site's authors.

A separate security related change is that WebSockets support was disabled by default for the final Opera 11 build, because of vulnerabilities recently discovered in the protocol.

The latest version of Opera for Windows can be downloaded from here.

The latest version of Opera for Linux can be downloaded from here.

The latest version of Opera for Mac can be downloaded from here.