Race condition in signal handling of procmail 3.20 and earlier, when running setuid, allows local users to cause a denial of service or gain root privileges by sending a signal while a signal handling routine is already running.
https://exchange.xforce.ibmcloud.com/vulnerabilities/6872
http://www.securityfocus.com/bid/3071
http://www.redhat.com/support/errata/RHSA-2001-093.html
http://www.linux-mandrake.com/en/security/2001/MDKSA-2001-085.php3
http://www.debian.org/security/2001/dsa-083
http://distro.conectiva.com.br/atualizacoes/?id=a&anuncio=000433