As hacking contest Pwn2Own is just a week away, web search firms Google and Mozilla have released patches to fix several vulnerabilities in their respective browsers.

Mozilla on Tuesday patched ten security holes in its browser Firefox, eight of which were rated "critical," while the remaining two were deemed as "High" and "Moderate" respectively.

The Firefox bugs ranges from a buffer overflow in JavaScript upvarMap to a use-after-free error in JSON. stringify. Both of these bugs were among the critical bugs. Other critical bug was the bug that was discovered by a security researcher, Jordi Chancel. This bug can cause a crash in case it is triggered by a tainted JPEG image.

Earlier, Google patched a total of nineteen security holes in Chrome web browser. The company rated three vulnerabilities as "Medium" and the remaining as "High."

Both Google and Mozilla released security patches for ahead of hacking contest Pwn2Own, which will take place at the CanSecWest Applied Security Conference from March 9 to March 11.

The annual hacking contest pits hackers against popular web browsers such as Chrome, Firefox, Safari and Internet Explorer. Participants will try to take down the most advanced versions of these popular browsers for grabbing $65,000 in prizes.