PGP Desktop 10.0.x before 10.0.3 SP2 and 10.1.0 before 10.1.0 SP1 does not properly implement the “Decrypt/Verify File via Right-Click” functionality for multi-packet OpenPGP messages that represent multi-message input, which allows remote attackers to spoof signed data by concatenating an additional message to the end of a legitimately signed message, related to a “piggy-back” or “unsigned data injection” issue.
secunia.com/advisories/42293
secunia.com/advisories/42307
www.cs.ru.nl/E.Verheul/papers/Govcert/Pretty%20Good%20Piggybagging%20v1.0.pdf
www.kb.cert.org/vuls/id/300785
www.securitytracker.com/id?1024760
www.symantec.com/security_response/securityupdates/detail.jsp?fid=security_advisory&pvid=security_advisory&year=2010&suid=20101118_00
exchange.xforce.ibmcloud.com/vulnerabilities/63366
pgp.custhelp.com/app/answers/detail/a_id/2290