Erroneous Stylesheet Caching

SeaMonkey is vulnerable to erroneous stylesheet caching. The CSSLoaderImpl::DoSheetComplete function in layout/style/nsCSSLoader.cpp changes the case of certain strings in a stylesheet before adding this stylesheet to the XUL cache, which might allow remote attackers to modify the browser’s font and other CSS attributes, and potentially disrupt rendering of a web page, by forcing the browser to perform this erroneous stylesheet caching.