WebKitGTK+ is vulnerable to use-after-free. It is due to flaws caused via a (1) font-face or (2) use element in an SVG document, allowing an attacker to use malicious web content to crash or, potentially, execute arbitrary code with the privileges of the user running the application.
lists.apple.com/archives/security-announce/2010//Jul/msg00001.html
lists.apple.com/archives/security-announce/2010//Nov/msg00003.html
lists.apple.com/archives/security-announce/2010//Sep/msg00002.html
lists.opensuse.org/opensuse-security-announce/2010-10/msg00000.html
lists.opensuse.org/opensuse-security-announce/2011-01/msg00006.html
secunia.com/advisories/41856
secunia.com/advisories/42314
secunia.com/advisories/43068
secunia.com/advisories/43086
support.apple.com/kb/HT4276
support.apple.com/kb/HT4334
support.apple.com/kb/HT4456
www.mandriva.com/security/advisories?name=MDVSA-2011:039
www.redhat.com/support/errata/RHSA-2011-0177.html
www.securityfocus.com/bid/42020
www.ubuntu.com/usn/USN-1006-1
www.vupen.com/english/advisories/2010/2722
www.vupen.com/english/advisories/2011/0212
www.vupen.com/english/advisories/2011/0216
www.vupen.com/english/advisories/2011/0552
access.redhat.com/errata/RHSA-2011:0177
access.redhat.com/security/updates/classification/#moderate
oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11923