GnuPG (gpg) 1.0.3 does not properly check all signatures of a file containing multiple documents, which allows an attacker to modify contents of all documents but the first without detection.
https://exchange.xforce.ibmcloud.com/vulnerabilities/5386
http://www.redhat.com/support/errata/RHSA-2000-089.html
http://www.debian.org/security/2000/20001111
http://distro.conectiva.com.br/atualizacoes/?id=a&anuncio=000334
http://archives.neohapsis.com/archives/bugtraq/2000-10/0361.html
http://archives.neohapsis.com/archives/bugtraq/2000-10/0201.html