CVE-2026-33217 (GCVE-0-2026-33217)

Vulnerability from cvelistv5 – Published: 2026-03-25 19:43 – Updated: 2026-03-25 20:08
VLAI?
Title
NATS allows MQTT clients to bypass ACL checks
Summary
NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, when using ACLs on message subjects, these ACLs were not applied in the `$MQTT.>` namespace, allowing MQTT clients to bypass ACL checks for MQTT subjects. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.
Severity ?
7.1 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N
CWE
  • CWE-863 - Incorrect Authorization
Assigner
References
Impacted products
Vendor Product Version
nats-io nats-server Affected: < 2.11.15
Affected: >= 2.12.0-RC.1, < 2.12.6
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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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Detection rules are retrieved from Rulezet.