LavinMQ is a high-performance message queue and streaming server used to facilitate asynchronous communication in distributed systems. CVE-2026-25767 is an authorization bypass vulnerability classified under CWE-863 (Incorrect Authorization). In versions of LavinMQ prior to 2.6.8, an authenticated user possessing the 'Policymaker' management tag can create shovels—components that transfer messages between virtual hosts (vhosts)—without proper access control enforcement. This flaw allows such users to read messages from vhosts they should not have access to and to publish messages to unauthorized vhosts. The vulnerability arises because the system fails to correctly verify the user's permissions when creating or managing shovels, effectively allowing privilege escalation within the messaging environment. Exploitation requires the attacker to be authenticated with at least Policymaker privileges but does not require additional user interaction or elevated privileges beyond that tag. The impact includes unauthorized disclosure of sensitive messages and potential injection of malicious or misleading messages into other vhosts, compromising confidentiality and integrity of inter-service communications. The vulnerability has a CVSS 4.0 score of 8.6, reflecting high severity due to network attack vector, low complexity, no user interaction, and high impact on confidentiality and integrity. The issue was publicly disclosed on February 12, 2026, and fixed in LavinMQ version 2.6.8. No known exploits have been reported in the wild to date, but the risk remains significant for environments using affected versions.

For European organizations, this vulnerability poses a serious risk to the confidentiality and integrity of internal messaging systems that rely on LavinMQ. Unauthorized access to messages across vhosts can lead to leakage of sensitive business data, intellectual property, or personal data protected under GDPR. Attackers could manipulate message flows, causing operational disruptions or injecting false data that may affect automated decision-making systems. Organizations using LavinMQ in multi-tenant or segmented environments are particularly vulnerable, as this flaw breaks isolation boundaries. The lack of requirement for user interaction and the ability to exploit remotely over the network increase the threat level. Given the widespread adoption of cloud messaging services in European enterprises, especially in finance, telecommunications, and critical infrastructure sectors, the impact could extend to regulatory non-compliance, reputational damage, and financial losses. Although no active exploits are known, the vulnerability’s high CVSS score and ease of exploitation warrant immediate remediation to prevent potential attacks.

European organizations should immediately upgrade all LavinMQ instances to version 2.6.8 or later to remediate this vulnerability. Until upgrades can be applied, restrict access to the management interface to trusted administrators only and enforce strict authentication and authorization policies, limiting the assignment of the 'Policymaker' tag to the minimum necessary personnel. Implement network segmentation and firewall rules to isolate messaging servers from untrusted networks. Monitor logs for unusual shovel creation activities or access patterns across vhosts. Conduct regular audits of user privileges and review configuration settings to ensure no unauthorized shovels exist. Employ anomaly detection tools to identify suspicious message flows that could indicate exploitation attempts. Additionally, consider deploying compensating controls such as message encryption at rest and in transit to reduce the impact of unauthorized message access. Finally, maintain an incident response plan tailored to messaging infrastructure compromises.