Improper input validation in Broadcom Rabbitmq Server
CVE-2026-67234
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.
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.004 (37.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 37.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.004 · change: -0.001
Affected products
- Broadcom Rabbitmq Server
- Rabbitmq Rabbitmq-Server — versions >= 4.2.0, < 4.2.8, >= 4.3.0, < 4.3.2
Weakness classification (CWE)
References
- https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-q286-p3m9-j69f (Vendor Advisory)
- https://github.com/rabbitmq/rabbitmq-server/commit/149cb59d618cefa83c6deb02dbbb1e8a7a2bc968 (Patch)
- https://github.com/rabbitmq/rabbitmq-server/commit/baac0aaf170efeb4f124ee36b8417274fa8dcc1a (Patch)
- https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.8 (Patch, Release Notes)
- https://github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.2 (Patch, Release Notes)
Frequently asked questions
- What is CVE-2026-67234?
- CVE-2026-67234 is a medium-severity vulnerability in Broadcom Rabbitmq Server, classified under Improper Input Validation. CVSS score: 4.3/10. Published 2026-09-25.
- How severe is CVE-2026-67234?
- Medium severity. CVSS v3 base score is 4.3 out of 10.