New Firefox, Mozilla Versions Plug Critical Security Holes

Third critical security update in less than two months fixes nine bugs in Firefox.

The Mozilla Foundation has released new versions of the Firefox browser and Mozilla suite of programs to address several security vulnerabilities.

As previously reported, the updates—Firefox 1.0.3 and Mozilla 1.7.7—patch a known JavaScript Engine flaw.

The vulnerabilities addressed by the new versions include three critical bugs in Firefox, two of which are also present in Mozilla. All seven vulnerabilities addressed in the Mozilla fix are also present in the Firefox upgrade, which also contains two fixes specific to it. No changes were announced in the Thunderbird mail client.

The three critical fixes involve two cases of arbitrary code execution and one of privilege escalation. In the first, an error in the support for "favicons" could allow a script to run with elevated privileges and install or run malicious software. The second, specific to Firefox, allows malicious scripts to open a privileged page in the sidebar and then inject script that can be used to install malicious code or steal data.

The third bug appears to involve UI code executing user scripts in an inappropriately privileged fashion. Mozilla is withholding further details on this bug until April 25.

Many of the noncritical bugs also involve serious compromises, such as privileged JavaScript execution and cross-site scripting.

The Mozilla Foundation had previously announced that it would not release any new major versions of the Mozilla Suite, but that it would continue to issue security updates. This release represents the third major set of security fixes in the Mozilla Suite and Firefox since late February.


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