CVE-2026-15916 in Drupal
Summary
by MITRE • 08/26/2026
Missing Authorization vulnerability in Drupal Drupal core allows Forceful Browsing. This issue affects Drupal core versions: from 0.0.0 to 10.6.13, from 11.3.0 to 11.3.14, from 11.4.0 to 11.4.4, from 0.0.0 to 11.0.*, from 0.0.0 to 11.1.*, from 0.0.0 to 11.2.*.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 08/26/2026
The identified vulnerability represents a critical failure in access control mechanisms within the Drupal core software, specifically classified as an improper authorization flaw that enables forceful browsing. This type of security issue arises when an application fails to properly verify whether an authenticated user has the necessary permissions to access specific resources or perform certain actions. In the context of web applications like Drupal, which serves a vast portion of the internet's content management infrastructure, such gaps can lead to significant data exposure and system compromise. The vulnerability affects multiple version ranges including 0.0.0 through 10.6.13, as well as various branches from 11.0.x up to 11.4.4, indicating a systemic issue that has persisted across several major releases of the platform.
From a technical perspective, this vulnerability allows attackers who have valid credentials or can bypass authentication mechanisms to access administrative functions, sensitive configuration data, or private user information without proper authorization checks. Forceful browsing occurs when an attacker systematically requests URLs or endpoints associated with privileged operations, relying on the server's failure to validate the requester's role against the requested resource. This is distinct from injection attacks or buffer overflows; it is purely a logic error in how permissions are enforced at the application layer. The absence of robust checks means that once an attacker gains any level of access, they can potentially escalate privileges by manipulating request parameters or directly accessing internal API endpoints designed for administrators only.
The operational impact of this vulnerability is severe due to Drupal's widespread adoption across enterprise and government sectors. Successful exploitation could lead to unauthorized modification of site configurations, theft of personally identifiable information stored in user profiles, defacement of public-facing websites, or complete takeover of the underlying server if administrative access leads to further exploits such as remote code execution via module uploads. The breadth of affected versions suggests that legacy systems running older Drupal instances are particularly at risk, while newer installations must ensure they have applied all relevant security patches up to version 10.6.14 and corresponding updates for the 11.x series.
This vulnerability aligns with CWE-285 Improper Authorization, which describes situations where an actor is able to access or modify data for which they should not be authorized. It also maps closely to MITRE ATT&CK technique T1078 Valid Accounts, as attackers often leverage stolen credentials combined with this authorization flaw to maintain persistence and expand their foothold within the network environment. The lack of strict enforcement allows lateral movement once initial access is established through other vectors such as phishing or credential stuffing.
Mitigation strategies must prioritize immediate patching by upgrading Drupal core to a version that includes fixes for these specific ranges, ensuring compliance with current security baselines. Administrators should also implement web application firewalls configured to detect and block patterns associated with forceful browsing attempts, such as repeated requests to administrative paths from non-admin IP addresses or user agents. Additionally, enforcing strict role-based access control policies and auditing login activity can help identify suspicious behavior indicative of exploitation attempts. Regular security assessments focusing on authorization logic are essential to prevent recurrence in custom modules or themes that may not inherit core fixes automatically.