Chained Quiz < 1.3.6 - Unauthenticated Insecure Direct Object Reference via Cookie

Description

The Chained Quiz plugin for WordPress is vulnerable to Insecure Direct Object Reference in version 1.3.4 and below via the quiz submission and completion mechanisms due to missing validation on a user controlled key. This makes it possible for unauthenticated attackers to hijack and modify other users' quiz attempts by manipulating the chained_completion_id cookie value, allowing them to alter quiz answers, scores, and results of any user. The vulnerability was partially patched in versions 1.3.4 and 1.3.5.