Home/CVE/NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The nats-server provides
CVE

CVE-2026-33215

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The nats-server provides

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The nats-server provides an MQTT client interface. Prior to versions 2.11.15 and 2.12.5, Sessions and Messages can by hijacked via MQTT Client ID malfeasance.

Versions 2.11.15 and 2.12.5 patch the issue. No known workarounds are available.

MEDIUM · CVSS 6.5 EPSS 0.00017
Monitor
  • No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-287Improper Authentication
CWE-488Exposure of Data Element to Wrong Session
▤

Affected Products & Versions

2
linuxfoundation nats-server>= 2.0.0 and < 2.11.15
linuxfoundation nats-server>= 2.12.0 and < 2.12.5
▤

Affected Packages

2
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
Go github.com/nats-io/nats-server
Go github.com/nats-io/nats-server/v2 MODERATE fixed in 2.11.15
▣

Scoring & Timeline

6.5
MEDIUM · CVSS v3.1 · security-advisories@github.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD24 Mar 2026 · 09:16 PM
CVSS VectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:L
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

2
rhsaRHSA-2026:21769Important
rhsaRHSA-2026:22347Important
🔗

References & Sources

2
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://advisories.nats.io/CVE/secnote-2026-06.txBroken Link
https://github.com/nats-io/nats-server/security/advisories/GHSA-fcjp-h8cc-6879Vendor Advisory
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