CVE-2026-67234 RabbitMQ: Non-RFC-conformant cookie name when clearing the auth-mechanism preference
RabbitMQ generates invalid cookie names when clearing auth preferences, potentially allowing stale authentication settings to persist across sessions.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-67234?
CVE-2026-67234 is a low-severity vulnerability in Broadcom Rabbitmq Server, published on 25 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-20
Which versions are affected by CVE-2026-67234?
1 open source package ship an affected version, including rabbitmq. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
rabbitmq Bitnami | From 4.2.0 | 4.2.8, 4.3.2 |
Products include Broadcom Rabbitmq Server.
How do I fix CVE-2026-67234?
Upgrade rabbitmq to a fixed version for your release line: 4.2.8 or 4.3.2.
Is CVE-2026-67234 being exploited?
There is no known exploitation of CVE-2026-67234 in the wild and no public exploit code.
Other vulnerabilities in Broadcom Rabbitmq Server
- CVE-2016-9877 Auth bypass in Pivotal RabbitMQ 3.x before 3.5.8 and 3.6.x before 3.6.6; RabbitMQ for PCF 1.5.x before 1.5.20, 1.6.x before 1.6.12 and 1.7.x before 1.7.7
- CVE-2026-67404 RabbitMQ: OAuth2 silent verify_none fallback for JWKS fetch
- CVE-2026-67231 RabbitMQ: Trust-store whitelist by Issuer+Serial only
- CVE-2026-57219 Information disclosure in rabbitmq-server
- CVE-2026-67236 RabbitMQ: Plaintext username:password stored in an insecure cookie after successful POST /login
Sources
Also known as BIT-rabbitmq-2026-67234, DEBIAN-CVE-2026-67234, GHSA-q286-p3m9-j69f, UBUNTU-CVE-2026-67234.