Mozilla users urged to upgrade

Users have been urged to upgrade to the latest versions of Mozilla's software to protect themselves from a series of critical security holes.

The U.S. Computer Emergency Readiness Team warned on Monday that earlier versions of Firefox, and other Mozilla software based on Firefox code, contain a clutch of vulnerabilities that expose users to attack.

The Mozilla Foundation released a new version of Firefox last week, version 1.5.0.2, which it said contained fixes for several security flaws.

According to security firm Secunia, there are a total of 21 flaws in the older versions of Firefox, such as Firefox 1.5, some of which it described as "highly critical".