CVE-2026-6564 Overview
A vulnerability has been identified in EMQ EMQX Enterprise up to version 6.1.0 affecting the Session Handling component. This improper authorization flaw allows attackers to bypass authorization controls remotely, potentially gaining unauthorized access to session-related functionality. The exploit has been publicly disclosed, and the vendor was contacted but did not respond to responsible disclosure attempts.
Critical Impact
Remote attackers can exploit improper authorization in session handling to bypass access controls in EMQX Enterprise deployments, potentially affecting availability of MQTT broker services.
Affected Products
- EMQ EMQX Enterprise up to version 6.1.0
Discovery Timeline
- 2026-04-19 - CVE-2026-6564 published to NVD
- 2026-04-22 - Last updated in NVD database
Technical Details for CVE-2026-6564
Vulnerability Analysis
This vulnerability is classified as CWE-266 (Incorrect Privilege Assignment), indicating that the EMQX Enterprise software fails to properly assign or manage privileges within its session handling mechanism. The flaw resides in an undisclosed function of the Session Handling component, where authorization checks are either missing or improperly implemented.
EMQX is a widely deployed MQTT message broker used in IoT and enterprise messaging scenarios. The session handling component is critical for managing client connections, subscriptions, and message routing. When authorization is improperly enforced in this component, attackers may be able to manipulate sessions they should not have access to.
The vulnerability can be exploited remotely over the network without requiring user interaction. An attacker with low-level privileges can potentially exploit this flaw to affect system availability. While the vulnerability does not directly compromise confidentiality or integrity according to the assessment, the improper authorization could serve as a stepping stone for more sophisticated attacks against MQTT infrastructure.
Root Cause
The root cause is improper authorization (CWE-266 - Incorrect Privilege Assignment) within the Session Handling component. The application fails to properly validate whether a user or client has the appropriate privileges to perform actions on session objects. This allows authenticated users with limited privileges to potentially access or manipulate sessions beyond their authorized scope.
Attack Vector
The attack can be launched remotely over the network. An attacker requires low-level authentication to exploit this vulnerability, meaning they need some form of valid credentials or session to initiate the attack. The exploitation does not require any user interaction, making it suitable for automated exploitation attempts.
The vulnerability has been publicly disclosed with exploit information available, increasing the risk of exploitation by malicious actors. Organizations running vulnerable versions of EMQX Enterprise should prioritize assessment and remediation.
Detection Methods for CVE-2026-6564
Indicators of Compromise
- Unusual session activity patterns including unauthorized session access attempts or modifications
- Authentication logs showing unexpected privilege escalation attempts in EMQX broker logs
- Anomalous API calls to session management endpoints from unexpected sources
- Multiple failed authorization attempts followed by successful session access
Detection Strategies
- Monitor EMQX Enterprise logs for authorization failures and anomalies in session handling operations
- Implement network monitoring to detect unusual traffic patterns to MQTT broker endpoints
- Deploy intrusion detection rules to identify exploitation attempts targeting session management APIs
- Review authentication and authorization logs for patterns consistent with privilege abuse
Monitoring Recommendations
- Enable detailed logging for session handling operations in EMQX Enterprise
- Configure alerts for failed authorization attempts and unusual session access patterns
- Monitor network connections to EMQX broker for unexpected remote access attempts
- Implement centralized log collection and analysis for MQTT infrastructure
How to Mitigate CVE-2026-6564
Immediate Actions Required
- Review and audit session handling configurations in EMQX Enterprise deployments
- Implement network segmentation to restrict access to MQTT broker management interfaces
- Apply additional authentication controls and monitor for exploitation attempts
- Consider temporarily restricting remote access to session management functionality if feasible
Patch Information
No official patch information has been released by the vendor at this time. The vendor was contacted about this disclosure but did not respond. Organizations should monitor EMQ's official channels for security updates and upgrade to a patched version when available.
For additional technical details, refer to the following resources:
Workarounds
- Implement strict network access controls to limit which systems can communicate with EMQX Enterprise instances
- Enable additional authentication mechanisms and review user privilege assignments
- Deploy a web application firewall (WAF) or API gateway to filter malicious requests to MQTT endpoints
- Conduct regular security audits of session handling configurations and access controls
# Example: Restrict network access to EMQX management ports using iptables
# Only allow access from trusted management network (adjust IP range as needed)
iptables -A INPUT -p tcp --dport 18083 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 18083 -j DROP
# Enable verbose logging for session operations in EMQX configuration
# Add to emqx.conf:
# log.level = debug
# log.to = file
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
