Mozilla confirms critical Firefox bug

Slates patch for March 30; flaw can't be used in upcoming Pwn2Own hack contest

Mozilla yesterday confirmed a critical vulnerability in the newest version of Firefox, and said it would plug the hole by the end of the month.

Although the patch won't be added to Firefox before next week's Pwn2Own browser hacking challenge, researchers won't be allowed to use the flaw, according to the contest's organizer.

"The vulnerability was determined to be critical and could result in remote code execution by an attacker," Mozilla acknowledged in a post to its security blog late Thursday. "The vulnerability has been patched by developers and we are currently undergoing quality assurance testing for the fix."

Firefox 3.6, which Mozilla launched in January, is affected, Mozilla said, adding that it would be patched in version 3.6.2, currently slated to ship on March 30.

The bug was disclosed by Russian researcher Evgeny Legerov a month ago in a message posted on a forum hosted by Immunity, the Miami Beach, Fla. developer best known for its Canvas penetration testing framework. Legerov works for Moscow-based Intevydis, which produces the VulnDisco add-on for Canvas.

Legerov did not publish attack code, and initially refused to provide details to Mozilla, according to a March 4 entry he posted on his blog. "I've ignored e-mails ... from Mozilla, please do not waste my and your time anymore," Legerov wrote. The blog has since been deleted, but is still available via Google's cache .

In comments appended to a vulnerability alert 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 downloading the preview .

Although Apple and Google have recently updated Safari and Chrome , respectively -- beefing up the browsers' security before the $100,000 Pwn2Own hacking contest 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.

Portnoy, who organized the fourth annual contest, has predicted that Microsoft 's IE8 will be the first browser to fall during the three-day event.

Mozilla will also patch Firefox 3.0 (with 3.0.19) and Firefox 3.5 (with 3.5.9) on March 30. Firefox 3.0.19 will be the final security update for the browser Mozilla debuted in mid-2008.

Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer or subscribe to Gregg's RSS feed . His e-mail address is .

metatag data

Read more about security in Computerworld's Security Knowledge Center.

Join the Good Gear Guide newsletter!

Error: Please check your email address.

Tags exploits and vulnerabilitiesFirefoxsecuritybrowserspwn2own

Our Back to Business guide highlights the best products for you to boost your productivity at home, on the road, at the office, or in the classroom.

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Gregg Keizer

Computerworld (US)
Show Comments

Cool Tech

D-Link PowerLine AV2 2000 Gigabit Network Kit

Learn more >

D-Link TAIPAN AC3200 Ultra Wi-Fi Modem Router (DSL-4320L)

Learn more >

Crucial® BX200 SATA 2.5” 7mm (with 9.5mm adapter) Internal Solid State Drive

Learn more >

Lexar® Professional 1000x microSDHC™/microSDXC™ UHS-II cards

Learn more >

ASUS ROG Swift PG279Q – Reign beyond virtual world

Learn more >

Xiro Drone Xplorer V -3 Axis Gimbal & 1080p Full HD 14MP Camera

Learn more >

Gadgets & Things

Lexar Professional 2000x SDHC™/SDXC™ UHS-II cards

Learn more >

Lexar® Professional 1000x microSDHC™/microSDXC™ UHS-II cards

Learn more >


Learn more >

Family Friendly

Lexar® Professional 1000x microSDHC™/microSDXC™ UHS-II cards

Learn more >

ASUS VivoPC VM62 - Incredibly Powerful, Unbelievably Small

Learn more >

Lexar Professional 2000x SDHC™/SDXC™ UHS-II cards

Learn more >

Stocking Stuffer

Lexar® Professional 1000x microSDHC™/microSDXC™ UHS-II cards

Learn more >

Lexar Professional 2000x SDHC™/SDXC™ UHS-II cards

Learn more >

Christmas Gift Guide

Click for more ›

Most Popular Reviews

Best Deals on Good Gear Guide

Latest News Articles


GGG Evaluation Team

Kathy Cassidy


First impression on unpacking the Q702 test unit was the solid feel and clean, minimalist styling.

Anthony Grifoni


For work use, Microsoft Word and Excel programs pre-installed on the device are adequate for preparing short documents.

Steph Mundell


The Fujitsu LifeBook UH574 allowed for great mobility without being obnoxiously heavy or clunky. Its twelve hours of battery life did not disappoint.

Andrew Mitsi


The screen was particularly good. It is bright and visible from most angles, however heat is an issue, particularly around the Windows button on the front, and on the back where the battery housing is located.

Simon Harriott


My first impression after unboxing the Q702 is that it is a nice looking unit. Styling is somewhat minimalist but very effective. The tablet part, once detached, has a nice weight, and no buttons or switches are located in awkward or intrusive positions.


Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?