Firefox 3 was downloaded 8.3 million time in the first 24 hours it was released, but the success was tempered by reports from a software security company that Firefox 3.0 contained a serious security flaw that potentially lets a hacker take over a PC if a user clicks on a booby-trapped link.

About five hours after the official release, security software vendor Tipping Point found a “critical vulnerability” that effects both Firefox 3.0 and 2.0 and informed Mozilla of it. Tipping Point researchers gave it a “high” severity level.

Mozilla stated on the Firefox security blog that, “There is no public exploit, the details are private, and so the current risk to users is minimal. We are investigating the vulnerability.”

Firefox was downloaded so much that it initially crashed Mozilla’s servers.

Tipping Point only released information of the flaw to Mozilla, but news of the glitch was damaging to the browser that claimed to be much more secure than the previous version.