CVE-2022-21683 in Wagtail
Summary
by MITRE • 01/18/2022
Wagtail is a Django based content management system focused on flexibility and user experience. When notifications for new replies in comment threads are sent, they are sent to all users who have replied or commented anywhere on the site, rather than only in the relevant threads. This means that a user could listen in to new comment replies on pages they have not have editing access to, as long as they have left a comment or reply somewhere on the site. A patched version has been released as Wagtail 2.15.2, which restores the intended behaviour - to send notifications for new replies to the participants in the active thread only (editing permissions are not considered). New comments can be disabled by setting `WAGTAILADMIN_COMMENTS_ENABLED = False` in the Django settings file.
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Analysis
by VulDB Data Team • 01/26/2022
CVE-2022-21683 represents a significant information disclosure vulnerability within the Wagtail content management system that directly impacts the confidentiality and integrity of user communications. This flaw exists in the comment notification system where the application fails to properly isolate comment threads, resulting in users receiving notifications for replies in discussions they should not have access to. The vulnerability stems from improper access control implementation in the notification routing mechanism, where the system indiscriminately sends comment replies to all users who have previously engaged in any commenting activity across the entire site rather than restricting notifications to participants within specific threads. This misconfiguration creates a scenario where users with minimal site engagement can potentially monitor sensitive discussions they have no legitimate access to, fundamentally undermining the privacy expectations of content management system users. The flaw is categorized under CWE-284 Access Control Bypass, which specifically addresses insufficient access control mechanisms that allow unauthorized access to resources or information. From an operational perspective, this vulnerability creates a persistent monitoring capability for malicious actors who may have previously commented on any part of the site, enabling them to track responses to discussions they cannot edit or view directly. The issue directly violates the principle of least privilege and demonstrates a critical failure in implementing proper access controls for user-generated content notifications. The vulnerability exists at the application layer and can be exploited through normal user interaction without requiring elevated privileges or specialized tools, making it particularly concerning for organizations that rely on Wagtail for content management. The patched version 2.15.2 addresses this by implementing proper thread isolation in the notification system, ensuring that only users who are actively participating in a specific comment thread receive notifications for new replies. This fix aligns with the ATT&CK technique T1078 Valid Accounts, as it prevents unauthorized information access through legitimate user accounts that have been used for commenting activities. Organizations can also implement a temporary mitigation by disabling comments entirely through the Django settings parameter WAGTAILADMIN_COMMENTS_ENABLED = False, though this represents a more restrictive approach that may impact legitimate user engagement. The vulnerability highlights the importance of proper access control implementation in web applications and demonstrates how seemingly minor flaws in notification systems can create significant security implications. The issue affects the overall security posture of Wagtail installations and could potentially enable information leakage that violates privacy expectations and may constitute a breach of user confidentiality. Security teams should prioritize patching this vulnerability across all Wagtail installations and consider implementing additional monitoring for unauthorized access patterns in comment systems. The fix implemented in version 2.15.2 represents a proper access control mechanism that ensures notifications are restricted to relevant participants, thereby maintaining the integrity of user communication channels and preventing unauthorized information disclosure through comment thread monitoring. This vulnerability serves as a reminder of the critical importance of proper access control implementation in web applications, particularly in content management systems where user-generated content and communication channels are integral to the platform's functionality.