Twelve Firefox flaws fixed

The bugs "can be exploited by malicious people to bypass certain security restrictions, conduct cross-site scripting and HTTP response smuggling attacks, and potentially compromise a user’s system," according to vulnerability monitoring firm Secunia, which rated the Firefox flaws "highly critical."

Firefox 1.5.0.4 "is a security update that is part of our ongoing program to provide a safe internet experience for our customers," according to a Mozilla statement.

The latest update, released late last week, follows a tumultuous April for the company, when it patched 21 vulnerabilities. Experts say more flaws are being discovered in alternative web browsers, such as Firefox, because of their growing market share.

Mozilla also has released new versions of its Thunderbird email application – to correct eight vulnerabilities – and its SeaMonkey integrated internet application suite – to fix 10 flaws.

A SANS Internet storm center report said last month that threats against Firefox would grow with the browser’s popularity.

"Firefox continues to be seen as somewhat safer than IE, but it is no panacea," according to the report.