CVE-2026-67234
RabbitMQ: Non-RFC-conformant cookie name when clearing the auth-mechanism preference
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Description
RabbitMQ is a messaging and streaming broker. From 4.2.0 until 4.2.8 and 4.3.2, get_auth_mechanism/1 used term_to_binary/1 on the strict_auth_mechanism or preferred_auth_mechanism atom when clearing the corresponding cookie, producing a non-ASCII cookie name that violates RFC 6265 and can prevent the browser from deleting the preference. The issue is not directly exploitable for code execution or data exfiltration; its security relevance is limited to stale authentication-mechanism preferences persisting across logout and login cycles. This issue is fixed in versions 4.2.8 and 4.3.2.
Affected
Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.
Remediation
No guide yetNo remediation guidance has been written for this CVE yet. What the record does show:
Patch and advisory references
- https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-q286-p3m9-j69f
- https://github.com/rabbitmq/rabbitmq-server/commit/149cb59d618cefa83c6deb02dbbb1e8a7a2bc968
- https://github.com/rabbitmq/rabbitmq-server/commit/baac0aaf170efeb4f124ee36b8417274fa8dcc1a
- https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.8
- https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.2
References (5)
SSVC — Action Prioritization
SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.
CVSS
- Attack Vector
- NETWORK
- Complexity
- LOW
- Privileges
- NONE
- User Interaction
- REQUIRED
- Scope
- UNCHANGED
- Confidentiality
- NONE
- Integrity
- LOW
- Availability
- NONE
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