Four critical patches have been released by the Firefox browser.

An update was released on Thursday and should be picked up and installed through Firefox's automatic update system over the next few days, according to developer Mozilla.

Security company Secunia has rated 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."

In addition to the four critical patches, the software also fixes three less-critical issues and improves overall stability enhancements. Hackers have traditionally focused on Microsoft's Internet Explorer browser, but as Firefox's market share has grown, it has become a more attractive target. Firefox is now used by approximately 13 percent of web surfers.