Mozilla Firefox — свободный браузер на движке Gecko

Firefox 0.9, Thunderbird 0.6 and other versions before 0.9, and Mozilla 1.7 before 1.7.5 save temporary files with world-readable permissions, which allows local users to read certain web content or attachments that belong to other users, e.g. content that is managed by helper applications such as PDF.

Firefox before 1.0 and Mozilla before 1.7.5 display the secure site lock icon when a view-source: URL references a secure SSL site while an insecure page is being loaded, which could facilitate phishing attacks.

The favicon functionality in Firefox before 1.0.3 and Mozilla Suite before 1.7.7 allows remote attackers to execute arbitrary code via a <LINK rel="icon"> tag with a javascript: URL in the href attribute, aka "Firelinking."

Firefox before 1.0.3, Mozilla Suite before 1.7.7, and Netscape 7.2 allows remote attackers to replace existing search plugins with malicious ones using sidebar.addSearchEngine and the same filename as the target engine, which may not be displayed in the GUI, which could then be used to execute malicious script, aka "Firesearching 2."

Firefox before 1.0.1 and Mozilla before 1.7.6 does not restrict xsl:include and xsl:import tags in XSLT stylesheets to the current domain, which allows remote attackers to determine the existence of files on the local system.

The native implementations of InstallTrigger and other functions in Firefox before 1.0.3 and Mozilla Suite before 1.7.7 do not properly verify the types of objects being accessed, which causes the Javascript interpreter to continue execution at the wrong memory address, which may allow attackers to cause a denial of service (application crash) and possibly execute arbitrary code by passing objects of the wrong type.

Firefox before 1.0.1 and Mozilla before 1.7.6 allows remote malicious web sites to spoof the extensions of files to download via the Content-Disposition header, which could be used to trick users into downloading dangerous content.

The Form Fill feature in Firefox before 1.0.1 allows remote attackers to steal potentially sensitive information via an input control that monitors the values that are generated by the autocomplete capability.

Firefox before 1.0.2 allows remote attackers to execute arbitrary code by tricking a user into saving a page as a Firefox sidebar panel, then using the sidebar panel to inject Javascript into a privileged page.

Firefox before 1.0 and Mozilla before 1.7.5, when configured to use a proxy, respond to 407 proxy auth requests from arbitrary servers, which allows remote attackers to steal NTLM or SPNEGO credentials.