RabbitMQ: Web MQTT with PROXY Protocol enabled: a loopback-only user permission bypass
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- High
- Attack requirements
- Present
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · None · None
- Fix status
- Partial Red Hat: 1 fixed, 5 without a fix
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-863.
Summary
RabbitMQ is a messaging and streaming broker. From 3.13.0 until 3.13.18, 4.0.23, 4.1.14, 4.2.9, and 4.3.3, native MQTT and MQTT over WebSocket behind a trusted PROXY Protocol frontend could lose the proxy-derived client address before the MQTT authentication path checked loopback_users, causing the frontend-to-broker address to be treated as loopback. An attacker who can reach the trusted frontend and has valid credentials for a loopback-restricted account can therefore bypass the source-address restriction; the issue does not bypass password authentication. This issue is fixed in versions 3.13.18, 4.0.23, 4.1.14, 4.2.9, and 4.3.3.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| rabbitmq | rabbitmq-server | 4.3.0 to before 4.3.3; 4.2.0 to before 4.2.9; 4.1.0 to before 4.1.14; 4.0.0 to before 4.0.23; 3.13.0 to before 3.13.18 | 4.3.3, 4.2.9, 4.1.14, 4.0.23, 3.13.18 | Patch available | CNA |
- rabbitmq-server Vendorrabbitmq Affected 4.3.0 to before 4.3.3; 4.2.0 to before 4.2.9; 4.1.0 to before 4.1.14; 4.0.0 to before 4.0.23; 3.13.0 to before 3.13.18 Fixed in 4.3.3, 4.2.9, 4.1.14, 4.0.23, 3.13.18 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:broadcom:rabbitmq_server:*:*:*:*:*:*:*:* | 3.13.0 to before 3.13.18; 4.0.0 to before 4.0.23; 4.1.0 to before 4.1.14; 4.2.0 to before 4.2.9; 4.3.0 to before 4.3.3 | Vulnerable | Broadcom |
- cpe:2.3:a:broadcom:rabbitmq_server:*:*:*:*:*:*:*:* Versions 3.13.0 to before 3.13.18; 4.0.0 to before 4.0.23; 4.1.0 to before 4.1.14; 4.2.0 to before 4.2.9; 4.3.0 to before 4.3.3 Vulnerable ·Broadcom
Remediation
- Fix · CNA rabbitmq-server (rabbitmq) Fixed in 4.3.3, 4.2.9, 4.1.14, 4.0.23, 3.13.18
Red Hat 1 advisory
- RHSA-2026:67552 Released 2026-09-15 · Red Hat rating ImportantRed Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images rabbitmq-server4.3-4.3.6-1.hum1@aarch64, rabbitmq-server4.3-4.3.6-1.hum1@src, rabbitmq-server4.3-4.3.6-1.hum1@x86_64
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Hardened Images | Affected | No fix planned: Will not fix |
| Red Hat OpenStack Platform 13 (Queens) | Affected | No fix planned: Out of support scope |
| Red Hat OpenStack Platform 16.2 | Affected | No fix planned: Out of support scope |
| Red Hat OpenStack Platform 17.1 | Affected | No fix planned: Out of support scope |
| Red Hat OpenStack Platform 18.0 | Affected | No fix yet: Fix deferred |
| Red Hat Hardened Images | Fixed | RHSA-2026:67552 |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-67411
- 2026-10-09 CVSS score added · NVD
- 2026-10-18 Fix available: RHSA-2026:67552 · Red Hat
- 2026-10-18 Fix available: Red Hat Hardened Images · Red Hat
- 2026-10-18 CVSS score added · Red Hat
References
Patch 2
More rabbitmq vulnerabilities
- TI-2026-41154 Improper authentication in rabbitmq-server CVSS 3.1CRITICAL 10.0
- TI-2026-41149 RabbitMQ: UNC SSRF affecting the management UI on Windows CVSS 3.1CRITICAL 10.0
- TI-2026-41158 Resource allocation without limits in rabbitmq-server CVSS 3.1HIGH 7.5
- TI-2026-47695 RabbitMQ: OAuth2 Client Secret Exposed via Unauthenticated JavaScript Endpoint CVSS 4.0HIGH 8.2
- TI-2026-47694 RabbitMQ: JWKS Fetch Ignores HTTP Response Status Code - Signing Key Destruction Causes Authentication DoS CVSS 4.0HIGH 8.2
- TI-2026-45167 RabbitMQ Java client: Unvalidated Class.forName in JSON-RPC ProcedureDescription enables arbitrary class loading CVSS 4.0HIGH 7.5
Sources
- CVE-2026-67411 · CVE Program
- CVE-2026-67411 · NVD
- FIRST EPSS
- CVE-2026-67411 · Red Hat security data · CC BY 4.0
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