CVE-2026-58213Network attack vector

Protocol operation injection via unfiltered MQTT subscriptions

Published Jul 8, 2026 · Updated Jul 8, 2026

Protocol injection in NATS Server before 2.12.9 and 2.14.0-RC.1 through 2.14.0 allows remote authenticated users to inject NATS operations. The MQTT parser accepts protocol control characters in subscription filters, then forwards the converted filters as NATS subjects over route or leafnode streams without neutralizing the delimiters. An MQTT client permitted to create subscriptions can affect cluster nodes or accounts; anonymous MQTT removes the authentication gate.

CVSS severity7.1
High
EPSS probability0.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Protocol injection in NATS Server before 2.12.9 and 2.14.0-RC.1 through 2.14.0 allows remote authenticated users to inject NATS operations. The MQTT parser accepts protocol control characters in subscription filters, then forwards the converted filters as NATS subjects over route or leafnode streams without neutralizing the delimiters. An MQTT client permitted to create subscriptions can affect cluster nodes or accounts; anonymous MQTT removes the authentication gate.

The record

CVE
CVE-2026-58213
Published
Jul 8, 2026
Updated
Jul 8, 2026
Vendor
NATS
Product
NATS Server
Classifications
CWE-74, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 2.12.9
  2. Affected versionversion=>= 2.14.0-RC.1, < 2.14.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

NATS · NATS Serverversion=< 2.12.9; version=>= 2.14.0-RC.1, < 2.14.1

Published CVSS scores

7.1GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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