The Mozilla Foundation has released a new security patch for its Firefox internet browser and is urging users to install it.

The patch fixes a flaw in the software that handles animated GIF images that could cause a buffer overflow.

If a hacker embedded malicious code in an image it could conceivably enter a PC through the browser software, although no exploit code has yet been found in the wild.

"The Mozilla Foundation is deeply committed to providing its users with the safest internet experience possible," said Chris Hofmann, director of engineering at Mozilla.

"To deliver our users the experience they deserve, we must stay ahead of the curve in patching potential vulnerabilities. For example, the bug patched in this update has no known real world exploits, and we were able to provide a quick response."

The flaw came to light after work done by security researchers at Internet Security Systems but was fixed before they published their report. This is the second Firefox patch to be released in the past month. The buffer overflow patch is available here.