This was originally bug 194617, until Bugzilla barfed yesterday.  Entering
it again...

           Summary: CVE-2006-2779 Multiple Mozilla issues (CVE-2006-2781,
                    CVE-2006-2788)
           Product: Fedora Core
           Version: fc5
          Platform: All
        OS/Version: Linux
            Status: NEW
          Severity: urgent
          Priority: normal
         Component: firefox
        AssignedTo: caillon
        ReportedBy: mattdm
                CC: deisenst,wtogami

This issue also affects Fedora Core 5. A lot of the problems fixed in 1.5.0.4
don't seem that severe, but a few of these are serious enough to at least turn
some heads. And it's been public for a quite a while now.

+++ This bug was initially created as a clone of Bug #193906 +++

Text stolen from MITRE:

CVE-2006-2781
Double-free vulnerability in Mozilla Thunderbird before 1.5.0.4 and
SeaMonkey before 1.0.2 allows remote attackers to cause a denial of
service (hang) and possibly execute arbitrary code via a VCard that
contains invalid base64 characters.

CVE-2006-2779
Mozilla Firefox and Thunderbird before 1.5.0.4 allow remote attackers
to cause a denial of service (crash) and possibly execute arbitrary
code via (1) nested <option> tags in a select tag, (2) a
DOMNodeRemoved mutation event, (3) "Content-implemented tree views,"
(4) BoxObjects, (5) the XBL implementation, (6) an iframe that
attempts to remove itself, which leads to memory corruption.

-- Additional comment from bressers on 2006-06-02 16:22 EST --
These issues also affect RHEL2.1 and RHEL3

-- Additional comment from bressers on 2006-06-02 16:34 EST --
Also this issue:

CVE-2006-2788
Double-free vulnerability in the getRawDER function for nsIX509Cert in
Firefox allows remote attackers to cause a denial of service (hang)
and possibly execute arbitrary code via certain Javascript code.