CVE-2026-107427 in Event Post Plugin
Summary
by MITRE • 10/12/2026
Authorization Bypass Through User-Controlled Key vulnerability in NOUS Ouvert Utile et Simple Event post event-post allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects Event post: from n/a through 6.1.1.
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Analysis
by VulDB Data Team • 10/12/2026
The identified vulnerability represents a critical failure in access control mechanisms within the NOUS Ouvert Utile et Simple Event application, specifically affecting versions ranging from non-existent initial releases up to version 6.1.1. This flaw is categorized as an Authorization Bypass Through User-Controlled Key, which indicates that the system fails to properly validate whether the authenticated user has permission to access or modify a specific resource based on the key provided in the request. Instead of relying on server-side session data or secure identifiers tied directly to the user's identity, the application appears to trust an identifier supplied by the client side without sufficient verification against the current authentication context. This architectural weakness allows attackers to manipulate the input parameters to target resources belonging to other users or administrative entities that they should not have access to.
From a technical perspective, this vulnerability stems from insecure direct object references where the application uses user-supplied data as a primary key for database queries or internal logic without enforcing proper authorization checks. When an authenticated user attempts to perform actions such as creating, updating, or deleting events via the post event endpoint, the system likely accepts an identifier that maps directly to the target resource. If this identifier is not cross-referenced with the permissions associated with the active session token, any logged-in user can potentially alter their request payload to include identifiers belonging to other users. This bypasses the intended security levels and allows for unauthorized modification of data across different organizational boundaries or individual accounts within the system.
The operational impact of this vulnerability is severe, as it compromises the integrity and confidentiality of sensitive event data stored within the application. An attacker can exploit this flaw to view private events created by other users, modify critical details such as dates, locations, or descriptions without authorization, or even delete important records entirely. In enterprise environments where NOUS Ouvert Utile et Simple Event is used for scheduling meetings, managing projects, or coordinating team activities, such unauthorized access can lead to significant operational disruptions, data leakage, and loss of trust among users. Furthermore, if the application integrates with other systems via APIs that rely on this event data, the integrity issues could propagate downstream, affecting broader organizational workflows and compliance postures.
This vulnerability aligns closely with CWE-639, which describes Authorization Bypass Through User-Controlled Key, highlighting the failure to enforce proper access control policies when handling user-supplied identifiers. In terms of offensive security frameworks, this behavior is consistent with techniques found in MITRE ATT&CK under privilege escalation or unauthorized data access categories, where adversaries leverage weak identity management controls to move laterally within a system or extract sensitive information. The lack of robust server-side validation means that the application relies heavily on client-side enforcement, which is inherently unreliable and easily circumvented using standard web proxy tools like Burp Suite or OWASP ZAP by simply altering request parameters during transmission.
To mitigate this vulnerability, developers must implement strict server-side authorization checks for all endpoints handling sensitive data operations. Specifically, every API call that accepts a resource identifier should verify that the authenticated user associated with the current session has explicit permission to access that specific instance of the resource. This can be achieved by maintaining an association between users and their resources in the database and validating this relationship before processing any write or read requests. Additionally, implementing indirect object references where internal IDs are mapped to opaque, non-guessable tokens for external use can reduce the risk of enumeration attacks. Regular security audits and penetration testing focusing on access control logic are essential to ensure that these safeguards remain effective against evolving attack vectors.