CVE-2026-65011 in Server
Summary
by MITRE • 07/22/2026
Graylog2 Server before commit 46a2eeb contains a missing per-entity permission check in the POST /events/definitions/{definitionId}/duplicate endpoint that allows authenticated users to clone any event definition. Attackers with the low-privilege eventdefinitions:create capability can read private event definitions including detection queries, aggregation thresholds, grouping fields, schedules, and notification bindings by duplicating them.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 07/22/2026
The vulnerability identified in Graylog2 Server represents a critical authorization flaw that undermines the security model of the platform through a missing per-entity permission check. This issue affects versions prior to commit 46a2eeb and specifically targets the POST /events/definitions/{definitionId}/duplicate endpoint, which is designed to allow users to create copies of existing event definitions. The flaw occurs because the system fails to validate whether the authenticated user has proper authorization rights to access the target event definition before permitting the duplication operation.
The technical implementation of this vulnerability stems from insufficient access control validation within the event definition duplication mechanism. When an authenticated user invokes the duplicate endpoint, the system should verify that the user possesses appropriate permissions not only to create new event definitions but also to read the specific definition being duplicated. However, the current implementation bypasses this crucial check, allowing any user with the minimal eventdefinitions:create capability to clone event definitions regardless of their ownership or access restrictions. This oversight creates a privilege escalation scenario where low-privileged users can effectively bypass security controls designed to protect sensitive event configuration data.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass potential exposure of critical security infrastructure information. Attackers exploiting this flaw can systematically enumerate and duplicate private event definitions, thereby gaining access to sensitive detection queries that may contain proprietary threat intelligence patterns, aggregation thresholds that indicate security monitoring configurations, grouping fields that define how alerts are organized, scheduling parameters that reveal operational workflows, and notification bindings that could expose communication channels and contact information for security incidents. This comprehensive data leakage capability significantly undermines the platform's ability to maintain confidential security operations and can provide attackers with detailed insights into the organization's threat detection capabilities.
The vulnerability aligns with CWE-639 Access Control Bypass and represents a specific instance of insufficient authorization checks as outlined in the CWE taxonomy. From an adversarial perspective, this flaw maps directly to techniques described in the MITRE ATT&CK framework under the Privilege Escalation and Credential Access domains, particularly relevant to tactics such as "Exploitation for Privilege Escalation" and "Tactic: Credential Access." The attack vector involves leveraging legitimate platform functionality to perform unauthorized operations, making detection more challenging since the actions appear to be normal user activities within the system.
Organizations should implement immediate mitigations including updating to Graylog2 Server version 46a2eeb or later where the permission check has been properly implemented. Additionally, security teams should review and audit existing event definitions to identify any potential unauthorized duplication that may have occurred before the patch was applied. Network monitoring should be enhanced to detect unusual patterns of event definition duplication activities, particularly from users with minimal privileges. The system should also enforce stricter access controls on sensitive configuration data through role-based access control policies that ensure users can only duplicate event definitions they have legitimate authorization to access, preventing unauthorized enumeration and extraction of critical security infrastructure information.