/sbin/passwd in HP-UX B.11.00, B.11.11, and B.11.23 before 20060326 "does not recover gracefully from some error conditions," which allows local users to cause a denial of service.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A1690
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A1660
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A1412
https://exchange.xforce.ibmcloud.com/vulnerabilities/25596
http://www2.itrc.hp.com/service/cki/docDisplay.do?docId=c00619550
http://www.vupen.com/english/advisories/2006/1208