The update fixes the Script object flaw which affected the XPCNativeWrapper and a crash problem that could corrupt memory, both of which had been rated critical by Mozilla.
Mozilla also provided a new fix for the URI problem that was discovered three months ago.
The company had patched the vulnerability as part of Firefox 184.108.40.206, but admitted that the fix hadn't completely solved the problem.
"That mitigation did not prevent the incorrect file-handling programs from launching, which left some risk," Mozilla's advisory stated.
"An additional fix has been applied to Firefox 220.127.116.11 that detects when Windows would mishandle these URIs so that the wrong program does not get launched."
Despite developing the latest version to work with Apple's Leopard operating system, Mozilla admitted that the browser is not fully compatible with Mac OS X 10.5.
A number of issues still need to be resolved, including problems displaying Flash movies on Intel-based Macs, integration of media plug-ins and issues with items in the Add-ons dialogue box.
Version 18.104.22.168 also adds two new languages, Romanian and Georgian.
Mozilla fixes Firefox flaws, welcomes Leopard
By Matt Chapman on Oct 23, 2007 7:29AM