Mozilla fixes Firefox zero-day vulnerability

published 17 July 2009

Mozilla has patched a zero-day vulnerability found in its Firefox 3.5 browser, which was only released at the end of last month.

Firefox 3.5.1 fixes a flaw in the browser's Just-in-time JavaScript compiler that Mozilla developers had said could allow hackers to execute malicious code on a user's computer.

The vulnerability was found a week after Firefox 3.5 was made available, but was made public this week and Mozilla patched it in the space of a couple of days.

As well as the security issue, the patch fixes several stability issues, including one that was making Firefox take a long time to load on particular Windows systems.

In a blog post, Mozilla strongly recommended that all Firefox 3.5 users upgraded to the latest release. This is available as an automatic update, but can also be applied manually using check for updates' from the Help menu.

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