CVE-2026-33215
MEDIUM6.5EPSS 0.02%NATS is vulnerable to MQTT hijacking via Client ID
Published: 3/24/2026Modified: 3/27/2026
Description
### 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 Sessions and Messages can by hijacked via MQTT Client ID malfeasance. ### Affected Versions Any version before v2.12.6 or v2.11.15 ### Workarounds None. ### Resources * This document is canonically: <https://advisories.nats.io/CVE/secnote-2026-06.txt> * GHSA advisory: <https://github.com/nats-io/nats-server/security/advisories/GHSA-fcjp-h8cc-6879> * MITRE CVE entry: <https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-33215>
Affected packages (5)
- Bitnami/natsfrom 0, < 2.11.15, >= 2.12.0, < 2.12.6
- Debian/nats-serverfrom 0
- Go/github.com/nats-io/nats-serverfrom 0
- Go/github.com/nats-io/nats-server/v2from 0, < 2.11.15
- Go/github.com/nats-io/nats-server/v2from 0, < 2.11.15, >= 2.12.0-RC.1, < 2.12.6
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.5 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:L |
References (6)
- ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2026-33215
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2026-33215
- PATCHhttps://github.com/nats-io/nats-server
- WEBhttps://advisories.nats.io/CVE/secnote-2026-06.tx
- WEBhttps://github.com/nats-io/nats-server/security/advisories/GHSA-fcjp-h8cc-6879
- WEBhttps://pkg.go.dev/vuln/GO-2026-4833