CVE-2026-25627Public exploitNetwork attack vector

Broker crash via unchecked WebSocket Remaining Length

Published Mar 30, 2026 · Updated Mar 30, 2026

Out-of-bounds read in NanoMQ before 0.24.8 allows remote attackers to crash the broker via a malformed MQTT WebSocket packet. In ws_msg_adaptor(), Remaining Length controls nni_msg_append() without checking the bytes available after the parsed header. The WebSocket listener must be enabled, and a valid CONNECT followed by a short malformed PUBLISH causes process termination and interrupts connected clients.

CVSS severity6.5
Medium
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in NanoMQ before 0.24.8 allows remote attackers to crash the broker via a malformed MQTT WebSocket packet. In ws_msg_adaptor(), Remaining Length controls nni_msg_append() without checking the bytes available after the parsed header. The WebSocket listener must be enabled, and a valid CONNECT followed by a short malformed PUBLISH causes process termination and interrupts connected clients.

The record

CVE
CVE-2026-25627
Published
Mar 30, 2026
Updated
Mar 30, 2026
Vendor
EMQ Technologies
Product
NanoMQ
Classifications
CWE-125, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 30, 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=< 0.24.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

EMQ Technologies · NanoMQversion=< 0.24.8

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
6.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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.

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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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1499.004Application or System Exploitation

Public exploit references

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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