Mozilla security researcher Georgi Guninski reported that scriptable plugin content, such as Flash objects, could be loaded and executed in SeaMonkey mail messages by embedding the content in an iframe inside the message. If a user were to reply to or forward such a message, malicious JavaScript embedded in the plugin content could potentially steal the contents of the message or files from the local filesystem.
Public now via: http://www.mozilla.org/security/announce/2010/mfsa2010-06.html
This issue was corrected in Red Hat Enterprise Linux 3 and 4 via: https://rhn.redhat.com/errata/RHSA-2009-1531.html as referenced in the seamonkey.spec: # fixed in 1.9.0.15 ... Patch378: mozilla-371976-x.patch Which corresponds to the linked mozilla bug in the upstream advisory: https://bugzilla.mozilla.org/show_bug.cgi?id=371976