A use after free issue exists in WebKit's handling of CSS run-ins. Visiting a maliciously crafted website may lead to an unexpected application termination or arbitrary code execution. This issue is addressed through improved handling of CSS run-ins. References: Bugzilla: https://bugs.webkit.org/show_bug.cgi?id=27193, https://bugs.webkit.org/show_bug.cgi?id=38625 Trac: http://trac.webkit.org/changeset/45941 Acknowledgements: Red Hat would like to thank Drew Yao of Apple Product Security for responsibly reporting this issue. Upstream acknowledges wushi of team509, working with TippingPoint's Zero Day Initiative, as the original reporter.
The above upstream commit is included in current webkitgtk (F12+) and qt packages.
This particular flaw doesn't affect khtml. The SVG testcase is very simplistic and straightforward. It's clear this variant does not affect khtml. As a percautionary measure, it may make sense to modify khtml to check for anonymous blocks, but not because of this flaw. The issue at hand is that during the destruction of the object, the anonymous blocks are mishandled. This is due to the render engine though, not to anonymous block itself. It is well known that the khtml and webkit render engines are drastically different. The fact that this issue doesn't affect khtml is not a surprise.
Public via: [1] http://support.apple.com/kb/HT419