CVE-2026-25768 Overview
CVE-2026-25768 is a Missing Authorization vulnerability (CWE-862) affecting LavinMQ, a high-performance message queue and streaming server. Before version 2.6.6, an authenticated user could access metadata in the broker that they should not have access to. This authorization bypass allows attackers with valid but low-privilege credentials to enumerate and retrieve sensitive broker metadata across virtual hosts they are not permitted to access.
Critical Impact
Authenticated users can bypass vhost-level access controls to access unauthorized broker metadata, potentially exposing sensitive queue configurations, connection details, and system information.
Affected Products
- LavinMQ versions prior to 2.6.6
- LavinMQ HTTP API endpoints handling vhost parameters
- Systems relying on LavinMQ vhost isolation for multi-tenant deployments
Discovery Timeline
- 2026-02-12 - CVE-2026-25768 published to NVD
- 2026-02-12 - Last updated in NVD database
Technical Details for CVE-2026-25768
Vulnerability Analysis
This vulnerability stems from missing authorization checks in the LavinMQ HTTP API controller. The with_vhost method, which handles vhost parameter resolution for API requests, failed to verify whether the authenticated user had permission to access the requested virtual host before yielding access to the vhost object.
When an authenticated user made requests to API endpoints that required vhost context, the controller would validate that the vhost existed but did not enforce access control policies. This allowed any authenticated user to access metadata and perform operations on virtual hosts they were not authorized to access, breaking the multi-tenant isolation model that organizations rely on for security segmentation.
The vulnerability is particularly concerning in shared or multi-tenant LavinMQ deployments where different users or applications are expected to be isolated to their own virtual hosts.
Root Cause
The root cause is the absence of authorization verification in the with_vhost method within src/lavinmq/http/controller.cr. The original implementation checked only for vhost existence but did not call refuse_unless_vhost_access to verify the user's permissions before granting access to the vhost context.
Attack Vector
The attack can be executed remotely over the network by any authenticated user. An attacker with valid credentials to one virtual host can craft HTTP API requests targeting other virtual hosts, effectively bypassing the intended access control boundaries. The attack requires low privilege (basic authentication) and no user interaction, making exploitation straightforward once valid credentials are obtained.
raise HaltRequest.new(body.try { |b| b[:reason] })
end
- private def with_vhost(context, params, key = "vhost", &)
- if (name = params[key]?) && (vhost = @amqp_server.vhosts[name]?)
+ private def with_vhost(context, params, *, vhost_key = "vhost", &)
+ if (name = params[vhost_key]?) && (vhost = @amqp_server.vhosts[name]?)
+ refuse_unless_vhost_access(context, user(context), vhost)
yield vhost
else
- not_found(context, "Not Found")
+ access_refused(context)
end
context
end
Source: GitHub Commit Update
Detection Methods for CVE-2026-25768
Indicators of Compromise
- HTTP API requests from authenticated users targeting vhosts they are not assigned to
- Unexpected enumeration of vhost metadata across the broker
- Access logs showing users querying multiple virtual hosts when their permissions restrict them to one
- Anomalous patterns of vhost-limits endpoint access with different vhost parameters
Detection Strategies
- Monitor LavinMQ HTTP API access logs for users accessing vhosts outside their authorized scope
- Implement alerting for failed authorization attempts that may indicate reconnaissance activity
- Review audit logs for cross-vhost metadata access patterns
- Deploy application-layer monitoring to detect parameter manipulation in vhost-related API calls
Monitoring Recommendations
- Enable detailed access logging on the LavinMQ HTTP API
- Configure SIEM rules to correlate user authentication with vhost access patterns
- Establish baseline behavior for legitimate vhost access and alert on deviations
- Monitor for increased API activity from accounts with limited vhost permissions
How to Mitigate CVE-2026-25768
Immediate Actions Required
- Upgrade LavinMQ to version 2.6.6 or later immediately
- Audit access logs for any historical unauthorized vhost access attempts
- Review and validate vhost permission configurations for all users
- Consider implementing network segmentation to limit API access to trusted sources
Patch Information
The vulnerability is fixed in LavinMQ version 2.6.6. The patch adds proper authorization checks by calling refuse_unless_vhost_access(context, user(context), vhost) before yielding access to vhost operations. Additionally, the error response was changed from not_found to access_refused to prevent information disclosure about vhost existence.
The fix is available via:
Workarounds
- Restrict HTTP API access to trusted networks only using firewall rules
- Implement additional authentication layers (e.g., API gateway) in front of LavinMQ
- Disable the HTTP management API if not required for operations
- Apply principle of least privilege by minimizing the number of authenticated users
# Example: Restrict LavinMQ HTTP API access to trusted networks via firewall
iptables -A INPUT -p tcp --dport 15672 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 15672 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
