crontab in Vixie cron 3.0.1 and earlier does not properly drop privileges after the failed parsing of a modification operation, which could allow a local attacker to gain additional privileges when an editor is called to correct the error.
https://exchange.xforce.ibmcloud.com/vulnerabilities/6508
https://euvd.enisa.europa.eu/vulnerability/EUVD-2001-0551
http://www.securityfocus.com/bid/2687
http://www.securityfocus.com/archive/1/183029
http://www.novell.com/linux/security/advisories/2001_017_cron_txt.html
http://www.linux-mandrake.com/en/security/2001/MDKSA-2001-050.php3