Mozilla developers have updated their Firefox browser to fix a number of security issues, four of them rated critical.

The update was released late Thursday, and Firefox users should receive the patches via the browser's automatic update system over the next few days, according to Mozilla.

Research firm Secunia rates the flaws as "highly critical," saying that they can be exploited to "conduct man-in-the-middle, spoofing, and cross-site scripting attacks, and potentially compromise a user's system," according to an alert.

Web surfers who want to download the Firefox update directly can find it here.

In addition to the four critical patches, the software also fixes three less-critical issues and offers some stability enhancements according to the Mozilla. Details on the security vulnerabilities can be