In comments appended to a published by Danish bug tracker Secunia, several users questioned Legerov's motives for making the announcement, while others chided Secunia for not thoroughly testing the flaw or claimed that it was all a hoax.

Mozilla yesterday said Legerov had eventually sent them "sufficient details to reproduce and analyze the issue."

Until the March 30 patch is released, users can upgrade Firefox to the beta of version 3.6.2, which includes the fix, by .

Although and have recently updated and , respectively -- beefing up the browsers' security before the starts March 24 -- the version of Firefox that will be used in the challenge will lack the patch for Legerov's vulnerability. Pwn2Own will pit only production versions of Chrome, Firefox, Internet Explorer (IE) and Safari against the hacking talents of researchers.

However, that doesn't mean hackers will be able to use the bug to claim one of the $10,000 prizes for successfully exploiting Firefox. "We will have our entire research team on-site so that we can do our best to ensure that known issues such as this one do not turn up at our contest," said Aaron Portnoy, a research team lead with 3Com TippingPoint, the company sponsoring Pwn2Own.