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 products
broadcom: rabbitmq server
References5
- github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-q2… Vendor Advisory
- github.com/rabbitmq/rabbitmq-server/commit/149cb59d618cefa83c6d… Patch
- github.com/rabbitmq/rabbitmq-server/commit/baac0aaf170efeb4f124… Patch
- github.com/rabbitmq/rabbitmq-server/releases/tag/v4.2.8 Release NotesPatch
- github.com/rabbitmq/rabbitmq-server/releases/tag/v4.3.2 Release NotesPatch
Metrics
- CVSS 3.1
-
4.3
MEDIUM
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N - CVSS 4.0
-
2.3
LOW
Score source: CNA
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 37 · as of 9 November 2026
- CWE
- CWE-20
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