Security issues were identified and fixed in mozilla firefox and
thunderbird:

The SVG implementation in Mozilla Firefox 8.0, Thunderbird 8.0, and
SeaMonkey 2.5 does not properly interact with DOMAttrModified event
handlers, which allows remote attackers to cause a denial of service
(out-of-bounds memory access) or possibly have unspecified other
impact via vectors involving removal of SVG elements (CVE-2011-3658).

Multiple unspecified vulnerabilities in the browser engine in Mozilla
Firefox 4.x through 8.0, Thunderbird 5.0 through 8.0, and SeaMonkey
before 2.6 allow remote attackers to cause a denial of service (memory
corruption and application crash) or possibly execute arbitrary
code via vectors that trigger a compartment mismatch associated with
the nsDOMMessageEvent::GetData function, and unknown other vectors
(CVE-2011-3660).

YARR, as used in Mozilla Firefox 4.x through 8.0, Thunderbird 5.0
through 8.0, and SeaMonkey before 2.6, allows remote attackers to
cause a denial of service (application crash) or possibly execute
arbitrary code via crafted JavaScript (CVE-2011-3661).

Mozilla Firefox 4.x through 8.0, Thunderbird 5.0 through 8.0, and
SeaMonkey before 2.6 allow remote attackers to capture keystrokes
entered on a web page by using SVG animation accessKey events within
that web page (CVE-2011-3663).

Mozilla Firefox 4.x through 8.0, Thunderbird 5.0 through 8.0, and
SeaMonkey before 2.6 allow remote attackers to cause a denial of
service (application crash) or possibly have unspecified other impact
via an Ogg VIDEO element that is not properly handled after scaling
(CVE-2011-3665).