CVE-2026-66067: CWE-770: Allocation of Resources Without Limits or Throttling in rabbitmq rabbitmq-server
RabbitMQ is a messaging and streaming broker. Prior to versions 4.2.7 and 4.3.1, The stream open handler calls only check_vhost_access; it omits the node/vhost/user connection-limit checks that rabbit_reader performs for AMQP. A developer %% FIXME comment at the cited line explicitly acknowledges the gap. No compensating enforcement exists in connection tracking or elsewhere in rabbitmq_stream. An authenticated tenant can fully bypass operator-configured per-user and per-vhost connection caps by connecting via port 5552 instead of 5672. Preconditions include rabbitmq_stream plugin enabled Authenticated stream-protocol credentials Operator relies on per-user/per-vhost connection limits for tenant isolation. This issue is fixed in versions 4.2.7 and 4.3.1.
AI Analysis
Technical Summary
RabbitMQ's stream open handler prior to versions 4.2.7 and 4.3.1 only performs check_vhost_access and omits node/vhost/user connection-limit checks that are enforced for AMQP connections. This omission allows an authenticated tenant using the rabbitmq_stream plugin to bypass per-user and per-vhost connection limits by connecting through port 5552. The vulnerability is due to allocation of resources without limits or throttling (CWE-770). There is no compensating enforcement in connection tracking or elsewhere in rabbitmq_stream. The issue is resolved in versions 4.2.7 and 4.3.1.
Potential Impact
An authenticated tenant can bypass operator-configured connection limits per user and per virtual host by connecting via the stream protocol on port 5552. This can lead to resource exhaustion or tenant isolation failures, potentially impacting service stability or multi-tenant security. The vulnerability requires authentication and the rabbitmq_stream plugin to be enabled.
Mitigation Recommendations
Upgrade rabbitmq-server to version 4.2.7 or later, or 4.3.1 or later, where this issue is fixed. No other compensating controls are available as the vulnerability arises from missing enforcement in the stream open handler.
CVE-2026-66067: CWE-770: Allocation of Resources Without Limits or Throttling in rabbitmq rabbitmq-server
Description
RabbitMQ is a messaging and streaming broker. Prior to versions 4.2.7 and 4.3.1, The stream open handler calls only check_vhost_access; it omits the node/vhost/user connection-limit checks that rabbit_reader performs for AMQP. A developer %% FIXME comment at the cited line explicitly acknowledges the gap. No compensating enforcement exists in connection tracking or elsewhere in rabbitmq_stream. An authenticated tenant can fully bypass operator-configured per-user and per-vhost connection caps by connecting via port 5552 instead of 5672. Preconditions include rabbitmq_stream plugin enabled Authenticated stream-protocol credentials Operator relies on per-user/per-vhost connection limits for tenant isolation. This issue is fixed in versions 4.2.7 and 4.3.1.
CVSS v4.0
Score 6.0medium
Affected software
rabbitmq
rabbitmq-server
pkg:github/rabbitmq/rabbitmq-serverRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
RabbitMQ's stream open handler prior to versions 4.2.7 and 4.3.1 only performs check_vhost_access and omits node/vhost/user connection-limit checks that are enforced for AMQP connections. This omission allows an authenticated tenant using the rabbitmq_stream plugin to bypass per-user and per-vhost connection limits by connecting through port 5552. The vulnerability is due to allocation of resources without limits or throttling (CWE-770). There is no compensating enforcement in connection tracking or elsewhere in rabbitmq_stream. The issue is resolved in versions 4.2.7 and 4.3.1.
Potential Impact
An authenticated tenant can bypass operator-configured connection limits per user and per virtual host by connecting via the stream protocol on port 5552. This can lead to resource exhaustion or tenant isolation failures, potentially impacting service stability or multi-tenant security. The vulnerability requires authentication and the rabbitmq_stream plugin to be enabled.
Mitigation Recommendations
Upgrade rabbitmq-server to version 4.2.7 or later, or 4.3.1 or later, where this issue is fixed. No other compensating controls are available as the vulnerability arises from missing enforcement in the stream open handler.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-07-23T23:25:28.897Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6ab43797f7a7c541064a9650
Added to database: 09/23/2026, 20:33:27 UTC
Last enriched: 09/23/2026, 20:48:50 UTC
Last updated: 09/24/2026, 01:57:04 UTC
Views: 6
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