Gld is a standalone greylisting server for Postfix.
dong-hun discovered several buffer overflows in server.c, as well as several format string vulnerabilities in cnf.c.
An attacker could exploit this vulnerability to execute arbitrary code with the permissions of the user running Gld, the default user being root.
There is no known workaround at this time.
All Gld users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=mail-filter/gld-1.5"