NATS Server 2.11.15/2.12.6: MQTT passwords exposed via monitoring endpoint.
CVE-2026-33216 Published on March 25, 2026
NATS has MQTT plaintext password disclosure
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, for MQTT deployments using usercodes/passwords: MQTT passwords are incorrectly classified as a non-authenticating identity statement (JWT) and exposed via monitoring endpoints. Versions 2.11.14 and 2.12.6 contain a fix. As a workaround, ensure monitoring end-points are adequately secured. Best practice remains to not expose the monitoring endpoint to the Internet or other untrusted network users.
Vulnerability Analysis
CVE-2026-33216 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity and availability.
Weakness Types
Unprotected Storage of Credentials
Storing a password in plaintext may result in a system compromise. Password management issues occur when a password is stored in plaintext in an application's properties or configuration file. Storing a plaintext password in a configuration file allows anyone who can read the file access to the password-protected resource.
Exposure of Sensitive Information Due to Incompatible Policies
The product's intended functionality exposes information to certain actors in accordance with the developer's security policy, but this information is regarded as sensitive according to the intended security policies of other stakeholders such as the product's administrator, users, or others whose information is being processed.
Products Associated with CVE-2026-33216
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Affected Versions
nats-io nats-server:- Version < 2.11.15 is affected.
- Version >= 2.12.0-RC.1, < 2.12.6 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.