GnuPG is a utility for encrypting data and creating digital signatures.
Gerardo Richarte discovered that a number of applications that make use of GnuPG are prone to a vulnerability involving incorrect verification of signatures and encryption. An attacker could add arbitrary content to a signed message in such a way that a receiver of the message would not be able to distinguish between the properly signed parts of a message and the forged, unsigned, parts. (CVE-2007-1263)
Whilst this is not a vulnerability in GnuPG itself, the GnuPG team have produced a patch to protect against messages with multiple plaintext packets. Users should update to these erratum packages which contain the backported patch for this issue.
Red Hat would like to thank Core Security Technologies for reporting this issue.