The OSI dissector in Ethereal 0.9.12 and earlier allows remote attackers to cause a denial of service and possibly execute arbitrary code via invalid IPv4 or IPv6 prefix lengths, possibly triggering a buffer overflow.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A84
http://www.redhat.com/support/errata/RHSA-2003-077.html
http://www.ethereal.com/appnotes/enpa-sa-00010.html
http://www.debian.org/security/2003/dsa-324
http://secunia.com/advisories/9007
http://distro.conectiva.com.br/atualizacoes/?id=a&anuncio=000662