CVE-2026-22040Public exploitNetwork attack vector

Broker crash via concurrent MQTT message use-after-free

Published Mar 4, 2026 · Updated Mar 4, 2026

Use-after-free in NanoMQ 0.24.6 allows remote attackers to crash the broker through concurrent MQTT connection and messaging churn. The TCP transport send callback releases an MQTT message that concurrent session churn has already freed, corrupting the heap and causing an invalid-pointer abort. An MQTT connection and valid control packets are sufficient under default configuration, but reliable triggering requires high-frequency traffic and timing-dependent concurrency.

CVSS severity5.3
Medium
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in NanoMQ 0.24.6 allows remote attackers to crash the broker through concurrent MQTT connection and messaging churn. The TCP transport send callback releases an MQTT message that concurrent session churn has already freed, corrupting the heap and causing an invalid-pointer abort. An MQTT connection and valid control packets are sufficient under default configuration, but reliable triggering requires high-frequency traffic and timing-dependent concurrency.

The record

CVE
CVE-2026-22040
Published
Mar 4, 2026
Updated
Mar 4, 2026
Vendor
EMQ Technologies
Product
NanoMQ
Classifications
CWE-416, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 4, 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== 0.24.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

EMQ Technologies · NanoMQversion== 0.24.6

Published CVSS scores

5.3GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:R/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-416Use After Free
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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