CVE-2026-76610 in Zoo Extension
Summary
by MITRE • 08/20/2026
Joomla Extension - yootheme.com - Unauthenticated tag modifications in Zoo < 4.1.65 - The comment controller endpoint lacked ACL checks, allowing unauthorized tag modifications by unauthenticated users.
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Analysis
by VulDB Data Team • 08/20/2026
The vulnerability identified within the YOOtheme ZOO extension for Joomla versions prior to 4.1.65 represents a critical failure in access control mechanisms that permits unauthenticated actors to manipulate site metadata without valid credentials. This flaw specifically resides in the comment controller endpoint, which is designed to handle user interactions and feedback submissions on content items managed by the ZOO component. In a properly secured web application architecture, any operation that modifies persistent data or alters system state must be preceded by rigorous authentication verification and authorization checks to ensure that only privileged users can perform such actions. However, in this specific implementation, the endpoint responsible for processing tag modifications associated with comments lacks these essential Access Control List (ACL) validations. Consequently, an attacker who is not logged into the Joomla administrator panel or any other authenticated user role can directly interact with this API-like interface to alter tags assigned to content items.
From a technical perspective, the absence of ACL checks means that the server processes requests modifying tag associations based solely on the presence of specific parameters in the HTTP request body rather than verifying the identity and permissions of the requester. This allows for arbitrary write operations where an attacker can inject, remove, or modify tags linked to articles or items within the ZOO component. Tags are often used for categorization, filtering, and navigation purposes; therefore, their integrity is vital for maintaining the logical structure and usability of the website. By exploiting this flaw, a remote unauthenticated user can effectively deface the site by altering its metadata structure, potentially leading to misleading content organization or facilitating further attacks that rely on specific tag-based logic within other extensions or themes.
The operational impact of this vulnerability extends beyond simple data corruption. It undermines the trustworthiness of the website's content management system and can be leveraged as a stepping stone for more complex attack chains. For instance, if certain tags trigger specific JavaScript behaviors in templates or third-party plugins, an attacker could potentially influence those outcomes by manipulating tag values. Furthermore, this type of vulnerability contributes to information disclosure risks if the modified tags expose internal structures or sensitive categorization schemes that were not intended for public view. It also impacts availability and integrity metrics as defined in standard security frameworks, specifically aligning with CWE-862 which describes missing authorization checks, and CWE-913 regarding improper control of frequency of limiting resource consumption if the endpoint is abused to cause denial of service through excessive tag modifications.
In terms of threat modeling, this vulnerability maps directly to techniques observed in real-world attacks where attackers exploit weak access controls to deface websites or prepare for further exploitation. It corresponds to MITRE ATT&CK technique T1078 which involves valid accounts and potentially T1496 if the modification leads to resource hijacking through misleading categorization, although its primary classification remains under unauthorized modifications due to broken access control. The lack of authentication requirement makes this vulnerability particularly dangerous as it does not require any prior reconnaissance or credential theft; it can be exploited by anyone with network connectivity to the target server using standard web request tools.
To mitigate this risk, immediate action is required to update the YOOtheme ZOO extension to version 4.1.65 or later where these access control checks have been implemented and validated. Administrators should verify that all components are up to date with their latest security patches provided by the vendor. In addition to updating software, implementing a Web Application Firewall (WAF) can provide an additional layer of defense by detecting and blocking anomalous requests targeting comment controllers or tag modification endpoints without proper session tokens. Regular auditing of ACL configurations across Joomla extensions is also recommended to ensure that no other components suffer from similar oversights in permission validation logic.