CVE-2026-107257 in Actstream
Summary
by MITRE • 10/30/2026
Incorrect Authorization vulnerability in Drupal Actstream allows Forceful Browsing. This issue affects Actstream versions: from 0.0.0 to 2.0.1, from 2.1.0 to 2.1.1.
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Analysis
by VulDB Data Team • 10/30/2026
The identified security flaw within the Drupal Actstream module represents a critical failure in access control mechanisms, specifically categorized under CWE-639 as Authorization Bypass Through Forceful Browsing. This vulnerability exists across multiple versions of the software, including releases from 0.0.0 through 2.0.1 and subsequently from 2.1.0 to 2.1.1. The core issue stems from an insufficient validation of user permissions when handling requests directed at specific endpoints or resources managed by the Actstream module. In a properly secured application, every request must be authenticated and authorized based on the privileges associated with the requesting user account. However, in this instance, the system fails to adequately verify whether the current user has the requisite rights to access certain data or execute specific actions related to activity streams.
From an operational perspective, this authorization bypass allows attackers to interact with functionality that should be restricted to administrators or users with elevated privileges. By manipulating URLs or sending crafted HTTP requests, a malicious actor can force the server to process commands intended for higher-privileged accounts without possessing those credentials. This type of attack is often executed using automated tools that iterate through potential resource paths and parameters to discover unprotected endpoints. The impact of such an exploit can range from unauthorized viewing of sensitive activity logs and user interactions to potentially modifying or deleting stream entries, depending on the specific capabilities exposed by the vulnerable code path. In severe cases, if these actions involve administrative functions, it could lead to a complete compromise of the Drupal site's integrity and availability.
The technical root cause lies in the module’s handling of route definitions and permission checks within its PHP backend logic. The developers likely relied on default permissions or failed to explicitly enforce role-based access control for certain API endpoints or page callbacks associated with stream management. This oversight creates a gap where authenticated users, or even unauthenticated users if session validation is also flawed, can bypass intended restrictions. Such vulnerabilities are frequently mapped to the MITRE ATT&CK framework under techniques such as T1078 Valid Accounts and T1528 Steal Application Access Token, particularly if the attack involves leveraging existing sessions or tokens that were not properly scoped for specific actions.
To mitigate this vulnerability, immediate action is required by upgrading the Actstream module to a version where these authorization checks have been corrected. Drupal security advisories typically provide patched versions that address such flaws by implementing stricter permission validation logic before processing any request related to activity streams. Administrators should also ensure that their environments are configured with minimal privilege principles, ensuring that users operate under accounts with only the permissions necessary for their specific roles. Additionally, deploying a Web Application Firewall can help detect and block patterns associated with forceful browsing attacks by monitoring for unusual access attempts to restricted resources. Regular security audits and penetration testing focused on authorization flows are recommended to identify similar gaps in other modules or custom code within the Drupal installation.