All vulnerabilities
CVE-2026-66067GHSA-hwqx-2gfg-89qf

rabbitmq-server: RabbitMQ: Stream protocol skips per vhost per user connection limits

rabbitmq rabbitmq-server
Open in ThreatlineRecord JSON
CVSS
6.0Medium
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.35%Chance of exploitation activity in the next 30 days, higher than 27% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed inNone listedNo source names a fixed version. Check the vendor advisory below
Published23 Sep 2026Updated 24 Sep 2026CVE List

What fixes it

No source in this snapshot names a fixed version. The vendor advisories under References are the place to check.

Description

RabbitMQ is a messaging and streaming broker. Prior to versions 4.2.7 and 4.3.1, The stream open handler calls only check_vhost_access; it omits the node/vhost/user connection-limit checks that rabbit_reader performs for AMQP. A developer %% FIXME comment at the cited line explicitly acknowledges the gap. No compensating enforcement exists in connection tracking or elsewhere in rabbitmq_stream. An authenticated tenant can fully bypass operator-configured per-user and per-vhost connection caps by connecting via port 5552 instead of 5672. Preconditions include rabbitmq_stream plugin enabled Authenticated stream-protocol credentials Operator relies on per-user/per-vhost connection limits for tenant isolation. This issue is fixed in versions 4.2.7 and 4.3.1.

Text from CVE List

Affected versions 2

  • rabbitmq-serveraffected: >= 4.2.0, < 4.2.7CVE List
  • rabbitmq-serveraffected: >= 4.3.0, < 4.3.1CVE List

References 3