CVE-2026-2345 in Secure Exam Proctor Extension
Summary
by MITRE • 02/11/2026
Proctorio Chrome Extension is a browser extension used for online proctoring. The extension contains multiple window.addEventListener('message', ...) handlers that do not properly validate the origin of incoming messages. Specifically, an internal messaging bridge processes messages based solely on the presence of a fromWebsite property without verifying the event.origin attribute.
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Analysis
by VulDB Data Team • 02/11/2026
The vulnerability identified in CVE-2026-2345 affects the Proctorio Chrome Extension, a widely deployed browser extension designed for online proctoring purposes in educational and professional testing environments. This extension serves as a critical component in monitoring and securing remote assessments, making its security implications particularly significant given the sensitive nature of the data it handles and the trust placed in it by users. The extension's architecture relies on a messaging bridge mechanism to facilitate communication between different components, which creates a potential attack surface that adversaries can exploit through improper message validation.
The technical flaw resides in the extension's implementation of window.addEventListener('message', ...) handlers that demonstrate a critical security oversight in cross-origin message validation. Specifically, the internal messaging bridge processes incoming messages by examining only the presence of a fromWebsite property within the message payload without performing proper origin verification through the event.origin attribute. This design flaw directly violates fundamental security principles for cross-origin communication and represents a classic example of insecure direct object reference vulnerability. The absence of origin validation creates an opportunity for malicious actors to craft and send spoofed messages that appear legitimate to the extension's internal processing logic, effectively bypassing the security boundaries that should protect the extension's functionality.
The operational impact of this vulnerability extends beyond simple message interception, as it enables potential attackers to manipulate the extension's behavior and potentially access or modify sensitive data within the testing environment. An attacker could exploit this weakness to inject malicious payloads, manipulate test results, or gain unauthorized access to the proctoring session. The vulnerability's severity is compounded by the fact that it operates at the browser extension level, where the extension typically has elevated privileges and access to user data, making it a prime target for exploitation. This weakness could lead to unauthorized access to examination content, compromise test integrity, and potentially enable data exfiltration from the user's environment, representing a significant threat to the confidentiality and integrity of the proctoring process.
Security mitigation strategies should focus on implementing proper origin validation for all cross-origin message handlers within the extension. The recommended approach involves verifying the event.origin attribute against a predefined whitelist of trusted origins before processing any messages that contain the fromWebsite property. This implementation aligns with the principles outlined in CWE-284, which addresses improper access control in cross-origin communication scenarios, and follows the ATT&CK technique T1211 for privilege escalation through message manipulation. Additionally, developers should implement comprehensive logging of message processing activities to detect anomalous behavior and establish a more robust security posture for browser extensions handling sensitive data. The fix should also include implementing proper input validation and sanitization for all message parameters to prevent potential injection attacks that could exploit the same vulnerability pattern.