What the vulnerability does
01Description
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.
Explanation of Vulnerability in Simple Terms
02Summary
Chained Quiz versions 1.3.5 and earlier contain an integrity vulnerability that allows unauthenticated attackers to modify data over the network without user interaction. The vulnerability has a CVSS score of 5.3 (medium severity). No confidentiality or availability impact is present. Update to a version newer than 1.3.5 when available.
What an attacker can do
03Attacker Capabilities
Modify quiz data or settings without authentication.
Potential impact on your site
04Site Impact
Quiz content, answers, or scoring could be altered by unauthorized parties.
Conditions required to exploit
05Prerequisites
Network access only; no authentication or user interaction required.
Key dates
06Disclosure timeline
September 18, 2025
CVE published
April 8, 2026
Record updated
