accounts/ValidateAnswers in the security-questions implementation in ZOHO ManageEngine ADSelfService Plus before 4.5 Build 4500 makes it easier for remote attackers to reset user passwords, and consequently obtain access to arbitrary user accounts, via a modified (1) Hide_Captcha or (2) quesList parameter in a validateAll action.
https://exchange.xforce.ibmcloud.com/vulnerabilities/65350
http://www.vupen.com/english/advisories/2011/0392
http://www.securityfocus.com/archive/1/516396/100/0/threaded