"Some of these were crashes that showed evidence of memory corruption and we presume that at least some of these could be exploited to run arbitrary code with enough effort," the advisory said.

Users of Thunderbird could also be affected by the problem if they have JavaScript enabled, though this is not a recommend setting, the advisory noted.

Firefox has developed a reputation for being more secure and stable than Microsoft's Internet Explorer, which remains the dominant browser client. However, security experts attribute that in part to the smaller user base for Firefox making it a less attractive target for hackers, and Mozilla has always advised regular patching of the product.

Mozilla recently released an alpha version of Firefox 3.0, but that release is aimed at developers rather than general consumers.
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