CVE-2026-33217

mediumpriority · track · 26OT risk · elevatedEPSS 0.003 · 18 %ileDEEUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.26% (18th) EPSS
CVSS 6.5 · medium
Is it mine?
14 products
Check your exposure
Who says so?
5 sources
cnnvd · enisa_euvd · osv · cert_bund

EPSS · scored 2026-10-27

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.

01

cvss

Technical severity, 0–10. One row per scoring source.

8.1
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6–8.1

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:Nprimary · NVD / NIST USexploitability 3.9 · impact 2.5
v3.17.1highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:Nsecondary · ENISA EU
v3.17.1highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:Nsecondary · security-advisories@github.comexploitability 2.8 · impact 4.2
v3.18.1highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Nsecondaryexploitability 2.8 · impact 5.2
v3.17.1highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:Nsecondary · OSV
v3.16mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N/E:Usecondary · CVSS-BT (t0sche)
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-425USCWE-863USCWE-863US
04

affected products (14)

Products and version ranges known to be affected.

05

advisories (4)

Vendor and ecosystem advisories describing this.

  • WID-SEC-W-2026-0858NATS Server: Mehrere SchwachstellenDeutsch2026-03-24csaf · cert_bundDE

    Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in NATS Server ausnutzen, um Informationen offenzulegen oder zu manipulieren, einen Denial-of-Service zu verursachen und Sicherheitsmechanismen zu umgehen.

  • GHSA-jxxm-27vp-c3m5NATS allows MQTT clients to bypass ACL checks2026-03-24ghsa · osvUS

    ### Background NATS.io is a high performance open source pub-sub distributed communication technology, built for the cloud, on-premise, IoT, and edge computing. The nats-server provides an MQTT client interface. ### Problem Description 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. ### Affected Versions Any version before v2.12.6 or v2.11.15 ### Workarounds None.

  • BIT-nats-2026-33217NATS allows MQTT clients to bypass ACL checks2026-03-27vendor · osvUS

    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.

  • GO-2026-4834NATS allows MQTT clients to bypass ACL checks in github.com/nats-io/nats-server2026-03-26vendor · osvUS

    NATS allows MQTT clients to bypass ACL checks in github.com/nats-io/nats-server

06

also known as (6)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

cnnvdenisa_euvdosvcert_bundnvdNVDCVE.orgMITRE
published 2026-03-25modified 2026-09-09
08

references (14)

External citations — patches, advisories, analysis.

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