CVE-2024-42645Public exploitNetwork attack vector

Broker crash via retained-message topic alias

Published Jul 29, 2025 · Updated Jul 30, 2025

Reachable assertion in FlashMQ 1.14.0 allows remote attackers to crash the MQTT broker via a crafted retained publish message. When FlashMQ saves persistent session and subscription state, it accepts a retained message with a nonzero topic alias and reaches an assertion instead of rejecting that invalid state. An MQTT connection, a retained publish, and a persistent subscription are required; a successful trigger terminates the broker and interrupts service.

CVSS severity7.5
High
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reachable assertion in FlashMQ 1.14.0 allows remote attackers to crash the MQTT broker via a crafted retained publish message. When FlashMQ saves persistent session and subscription state, it accepts a retained message with a nonzero topic alias and reaches an assertion instead of rejecting that invalid state. An MQTT connection, a retained publish, and a persistent subscription are required; a successful trigger terminates the broker and interrupts service.

The record

CVE
CVE-2024-42645
Published
Jul 29, 2025
Updated
Jul 30, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-617, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 29, 2025CVE publishedPublication date reported by the CVE source.
  2. Jul 30, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/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-617Reachable Assertion
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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