Vulnerability Details CVE-2026-33217
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.003
EPSS Ranking 17.2%
CVSS Severity
CVSS v3 Score 7.1
References
- https://advisories.nats.io/CVE/secnote-2026-07.txt
- https://github.com/nats-io/nats-server/security/advisories/GHSA-jxxm-27vp-c3m5
- https://access.redhat.com/errata/RHSA-2026:21769
- https://access.redhat.com/errata/RHSA-2026:22347
- https://access.redhat.com/errata/RHSA-2026:23345
- https://access.redhat.com/security/cve/CVE-2026-33217
- https://bugzilla.redhat.com/show_bug.cgi?id=2451446
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33217.json
Products affected by CVE-2026-33217
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cpe:2.3:a:linuxfoundation:nats-server:2.12.0
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cpe:2.3:a:linuxfoundation:nats-server:2.12.1
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cpe:2.3:a:linuxfoundation:nats-server:2.12.2
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cpe:2.3:a:linuxfoundation:nats-server:2.12.3
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cpe:2.3:a:linuxfoundation:nats-server:2.12.4
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cpe:2.3:a:linuxfoundation:nats-server:2.12.5