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Vulnerability · Published Sep 25, 2026 · Assigned by GitHub_M

CVE-2026-67234RabbitMQ: Non-RFC-conformant cookie name when clearing the auth-mechanism preference

Low 2.3

In plain English

A low-severity improper input validation in rabbitmq-server from rabbitmq. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)2.3Low
Exploit odds (30 days)0.4%top 63.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:14rabbitmq-server4.3.2-1DEBIAN-CVE-2026-67234
Ubuntu:22.04:LTSrabbitmq-serverno fix listedUBUNTU-CVE-2026-67234
Ubuntu:24.04:LTSrabbitmq-serverno fix listedUBUNTU-CVE-2026-67234
Ubuntu:26.04:LTSrabbitmq-serverno fix listedUBUNTU-CVE-2026-67234

Affected products (as reported)

VendorProductVersions
rabbitmq rabbitmq-server >= 4.2.0, < 4.2.8>= 4.3.0, < 4.3.2

Weakness: CWE-20 · Vector: 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

References