vsftpd before 1.2.2, when under heavy load, allows attackers to cause a denial of service (crash) via a SIGCHLD signal during a malloc or free call, which is not re-entrant.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11049
https://exchange.xforce.ibmcloud.com/vulnerabilities/16222
http://www.securityfocus.com/bid/10394
http://secunia.com/advisories/11736
http://secunia.com/advisories/11680