IcedTea 1.7 before 1.7.8, 1.8 before 1.8.5, and 1.9 before 1.9.5 does not properly verify signatures for JAR files that (1) are "partially signed" or (2) signed by multiple entities, which allows remote attackers to trick users into executing code that appears to come from a trusted source.
https://exchange.xforce.ibmcloud.com/vulnerabilities/65151
http://www.ubuntu.com/usn/USN-1055-1
http://www.securityfocus.com/bid/46110
http://www.mandriva.com/security/advisories?name=MDVSA-2011:054
http://www.debian.org/security/2011/dsa-2224
http://security.gentoo.org/glsa/glsa-201406-32.xml
http://secunia.com/advisories/43135
http://icedtea.classpath.org/hg/release/icedtea-web-1.0?cmd=changeset%3Bnode=3bd328e4b515
http://blog.fuseyism.com/index.php/2011/02/01/security-icedtea6-178-185-195-released/