A flaw was found in the way Mutt used temporary files on NFS file systems. Due to an implementation issue in the NFS protocol, Mutt was not able to exclusively open a new file. A local attacker could conduct a time-dependent attack and possibly gain access to e-mail attachments opened by a victim. (CVE-2006-5297)
A flaw was found in the way Mutt processed certain APOP authentication requests. By sending certain responses when mutt attempted to authenticate against an APOP server, a remote attacker could potentially acquire certain portions of a user's authentication credentials. (CVE-2007-1558)
A flaw was found in the way Mutt handled certain characters in gecos fields which could lead to a buffer overflow. The gecos field is an entry in the password database typically used to record general information about the user. A local attacker could give themselves a carefully crafted "Real Name" which could execute arbitrary code if a victim uses Mutt and expands the attackers alias. (CVE-2007-2683)
All users of mutt should upgrade to this updated package, which contains a backported patches to correct these issues.