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.

CVSS v3 7.1 HIGH

7.1^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.8 / Impact : 4.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact LOW

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://advisories.nats.io/CVE/secnote-2026-07.txt	Vendor Advisory
https://github.com/nats-io/nats-server/security/advisories/GHSA-jxxm-27vp-c3m5	Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:linuxfoundation:nats-server::::::::
	cpe:2.3:a:linuxfoundation:nats-server::::::::

History

26 Mar 2026, 17:14

Type	Values Removed	Values Added
First Time		Linuxfoundation Linuxfoundation nats-server
References	~~() https://advisories.nats.io/CVE/secnote-2026-07.txt -~~	() https://advisories.nats.io/CVE/secnote-2026-07.txt - Vendor Advisory
References	~~() https://github.com/nats-io/nats-server/security/advisories/GHSA-jxxm-27vp-c3m5 -~~	() https://github.com/nats-io/nats-server/security/advisories/GHSA-jxxm-27vp-c3m5 - Vendor Advisory
CPE		cpe:2.3:a:linuxfoundation:nats-server::::::::

25 Mar 2026, 20:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-03-25 20:16

Updated : 2026-03-26 17:14

NVD link : CVE-2026-33217

Mitre link : CVE-2026-33217

CVE.ORG link : CVE-2026-33217

JSON object : View

Products Affected

linuxfoundation

nats-server

CWE

CWE-863

Incorrect Authorization

{"id": "CVE-2026-33217", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.1, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "LOW", "confidentialityImpact": "LOW"}, "impactScore": 4.2, "exploitabilityScore": 2.8}, {"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 6.5, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N", "integrityImpact": "LOW", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "LOW"}, "impactScore": 2.5, "exploitabilityScore": 3.9}]}, "published": "2026-03-25T20:16:32.473", "references": [{"url": "https://advisories.nats.io/CVE/secnote-2026-07.txt", "tags": ["Vendor Advisory"], "source": "security-advisories@github.com"}, {"url": "https://github.com/nats-io/nats-server/security/advisories/GHSA-jxxm-27vp-c3m5", "tags": ["Vendor Advisory"], "source": "security-advisories@github.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-863"}]}], "descriptions": [{"lang": "en", "value": "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."}], "lastModified": "2026-03-26T17:14:48.727", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "13EA156E-2759-4586-A22E-CDEAAD4D610C", "versionEndExcluding": "2.11.15"}, {"criteria": "cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "4E347CFB-C56D-4FD8-8DD8-3D34C08D7154", "versionEndExcluding": "2.12.6", "versionStartIncluding": "2.12.0"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}