CVE-2026-33217
Prior to versions 2.11.15 and 2.12.6, when using ACLs on message subjects, these ACLs were not applied in the `$MQTT.>` namespace, allowing MQTT clients to bypass ACL checks for MQTT subjects.
Does this matter?
Lower severity and a low EPSS score (0.26%). Track it; it rarely justifies an emergency change on its own.
Description
NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, when using ACLs on message subjects, these ACLs were not applied in the `$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.
- CVSS 3.1
- 6.5 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- EPSS
- 0.26% probability · 18th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-863, CWE-425
- Affected
- linuxfoundation/nats-server
- Source
- security-advisories@github.com
EPSS 0.3% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://advisories.nats.io/CVE/secnote-2026-07.txtVendor Advisory
- https://github.com/nats-io/nats-server/security/advisories/GHSA-jxxm-27vp-c3m5Vendor Advisory
- 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
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.