Some vulnerabilities have been reported in Opera, which can be exploited by malicious people to conduct spoofing and cross-site scripting attacks, bypass certain security restrictions, disclose potentially sensitive information, or potentially compromise a user's system.

1) An unspecified error exists when Opera is executed as a protocol handler. This can be exploited to cause a crash and potentially execute arbitrary code.

NOTE: Reportedly, the vulnerability only affects Opera for Windows.

2) The problem is that a web page can change the address of frames from other sites opened inside a pop-up window. This can be exploited to load malicious content into a frame of a trusted website.

3) An unspecified error can be exploited to conduct cross-site scripting attacks. No further information is currently available.

4) An error exists in the processing of custom shortcut and menu commands. This can be exploited to execute applications with potentially dangerous parameters, created from uninitialized memory.

Successful exploitation may allow execution of arbitrary code, but requires that a user is tricked into modifying shortcuts or menu files.

5) An error exists while reporting websites as secure for browsing. This can be exploited to determine the reporting of an insecure website as secure by including a frame with content from a secure website.

6) An error exists when checking if a web page links to a local file. This can be exploited to link to local feed source files and potentially determine if a file is present on the local system.

7) An error exists when processing news feed subscription requests. This can be exploited to change the address field to the address of the malicious web page and mislead a user.

The vulnerabilities are reported in versions prior to 9.52.

Opera users should upgrade their browser software following the discovery of multiple security bugs.

Version 9.5.2 of the Windows version of the software fixes seven vulnerabilities, including a startup crash that creates a means for hackers to inject hostile code on certain systems . There's also a fix for a cross-site scripting (XSS) bug, details of which Opera is withholding.

XSS flaws, in general, allow hackers to present the content of third party sites under their control in the context of a site they wish to impersonate. The approach is therefore useful in phishing attacks or other similar scams.

The Norwegian firm has published links to advisories about the other six security fixes. The latest version of the browser includes numerous stability and performance improvements as detailed in Opera's release notes

An overview of the vulnerabilities can be found in an advisory by security notification firm Secunia