CVE-2026-33216
Linuxfoundation Nats-Server ≤ 2.11.15
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:NCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-33216 is a high-severity Plaintext Storage of a Password (CWE-256) vulnerability in Linuxfoundation Nats-Server. Its CVSS base score is 8.6 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Data from Local System (T1005); ranked at the 30th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-16 (Security and Privacy Attributes) and AC-21 (Information Sharing) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-33216 is a vulnerability in NATS-Server, a high-performance server for the NATS.io cloud and edge native messaging system. It affects versions prior to 2.11.15 and 2.12.6, specifically in MQTT deployments that use usercodes and passwords. The issue arises because MQTT passwords are incorrectly classified as a non-authenticating identity statement in JWT format, resulting in their exposure through monitoring endpoints. The vulnerability is rated with a CVSS v3.1 base score of 8.6 (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N) and is associated with CWE-256 (Plaintext Storage of a Password).
Attackers can exploit this vulnerability remotely over the network with no privileges required, low complexity, and no user interaction needed. Anyone with access to the exposed monitoring endpoints can retrieve the MQTT passwords in plaintext, enabling unauthorized access to MQTT services. The scope change and high confidentiality impact allow attackers to compromise credentials without affecting integrity or availability.
Advisories and the patch notes recommend upgrading to versions 2.11.14 or 2.12.6, which contain the fix. As a workaround, administrators should ensure monitoring endpoints are adequately secured with authentication and access controls. Best practices emphasize not exposing the monitoring endpoint to the Internet or other untrusted networks, as detailed in the NATS security advisory and related GitHub commit.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-15964
Vulnerability Data
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…
more
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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 3 hardening rules · 3 OS baselines
V4.1.2V14.1.1V16.2.5V16.5.1
Mitigating Controls (NIST 800-53 r5) AI
Requiring confidentiality protection of information at rest directly stops passwords from being stored in plaintext.
Associates security and privacy attributes with data and subjects so that incompatible stakeholder policies can be reconciled before exposure occurs.
Requires explicit checking that a sharing partner's authorizations match the sensitivity of the information, preventing release under mismatched policies.
Enforces approved information flow policies between systems, directly stopping exposure when developer and stakeholder policies conflict.
Documents the specific purposes for processing PII, surfacing and aligning conflicting stakeholder policies before data exposure.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Understanding stakeholder needs directly surfaces incompatible sensitivity expectations that produce the exposure.
Regulatory and privacy obligations often define the conflicting sensitivity views that the weakness fails to reconcile.
Establishing risk-management policy based on organizational context is the primary mechanism for aligning divergent sensitivity rules.
Periodic policy review can detect and correct stakeholder-policy mismatches before they cause exposure.
Credential management practices normally include secure storage requirements for passwords.
Defining and enforcing access policy is one concrete place where incompatible sensitivity decisions manifest as unauthorized disclosure.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
High-level policy can mandate consistent handling of sensitive data across stakeholder expectations.
Classification directly addresses mismatched sensitivity views by defining what must be protected.
Labelling helps communicate classification decisions and reduce policy conflicts.
Transfer rules can enforce consistent protection when data crosses stakeholder boundaries.
Access control can limit exposure to actors whose policies differ from the developer’s.
Directly requires secure handling and protection of authentication information, preventing plaintext password storage.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (higher-evidence rows only; rows rated `none` are excluded).
Ubuntu 24.04 (1 rule)
- V-270708 Ubuntu 24.04 LTS must be configured so that remote X connections are disabled, unless to fulfill documented and validated mission requirements. prevents CWE-213
Windows Server 2019 (1 rule)
- V-205757 Windows Server 2019 Debug programs: user right must only be assigned to the Administrators group. prevents CWE-213