From Mozilla Foundation Security Advisory 2009-63:
Mozilla upgraded several third party libraries used in media rendering to address multiple memory safety and stability bugs identified by members of the Mozilla community. Some of the bugs discovered could potentially be used by an attacker to crash a victim's browser and execute arbitrary code on their computer. liboggz, libvorbis, and liboggplay were all upgraded to address these issues.
The flaw in Security Advisory 2009-57, found that the XPCOM utility XPCVariant::VariantDataToJS unwrapped doubly-wrapped objects before returning them to chrome callers. This enabled the possibility for bad code to be escalated to be executed with Chrome privileges.
The flaws in Mozilla aren't hurting its growth. Just yesterday Mozilla CEO John Lilly said in a Twitter post that Firefox grew by more than 30 million in the previous eight weeks. As of September 2009, web-analytics company Net Applications estimates nearly 24 percent of Internet browsers use Firefox.
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