Executive Summary

CVE-2025-10493 is an Insecure Direct Object Reference (IDOR) vulnerability in the WordPress Chained Quiz plugin (version 1.3.4 and below). It occurs because the plugin does not properly validate the ownership of a quiz completion record when processing quiz submissions and completions. An attacker can manipulate the 'chained_completion_id' cookie or URL parameters to hijack and modify other users' quiz attempts, altering their answers, scores, and results without authentication. The vulnerability was partially fixed in versions 1.3.4 and 1.3.5 by adding strict validation to ensure that the quiz completion record accessed belongs to the current user or session, using user ID checks for logged-in users and IP address checks for guests. [2]

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Impact Analysis

This vulnerability allows unauthenticated attackers to hijack and modify other users' quiz attempts by manipulating the 'chained_completion_id' cookie or URL parameters. As a result, attackers can alter quiz answers, scores, and results of any user, potentially compromising the integrity of quiz data. This could lead to inaccurate quiz outcomes, unfair scoring, and loss of trust in the quiz system. Additionally, unauthorized modification of quiz data could affect any processes or decisions based on quiz results. [2]

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Detection Guidance

The vulnerability involves manipulation of the 'chained_completion_id' cookie or URL parameters to hijack or modify quiz completions. Detection can focus on monitoring HTTP requests for suspicious or unexpected changes to the 'chained_completion_id' cookie or URL parameters related to quiz completions. Network or web server logs can be inspected for unusual patterns of these parameters. Specific commands are not provided in the resources, but general approaches include using web server log analysis tools or intrusion detection systems to flag requests with manipulated 'chained_completion_id' values. Additionally, inspecting cookies in browser developer tools or using proxy tools like Burp Suite to monitor and test the manipulation of this cookie can help detect exploitation attempts. [2]

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Mitigation Strategies

To mitigate this vulnerability, immediately update the Chained Quiz WordPress plugin to version 1.3.4 or later, as the vulnerability was fixed starting in version 1.3.4 with further improvements in 1.3.5 and 1.3.6. The fix includes strict validation of quiz completion ownership by verifying that the completion record belongs to the current user or session, preventing unauthorized access or modification. Additionally, ensure that your WordPress installation and plugins are kept up to date to benefit from security patches. If updating immediately is not possible, consider disabling the Chained Quiz plugin temporarily to prevent exploitation. [2, 5, 1]

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