CVE-2025-66217Public exploitNetwork attack vector

Remote service crash via MQTT length underflow

Published Nov 29, 2025 · Updated Dec 1, 2025

Integer underflow in AIS-catcher before 0.64 allows remote attackers to crash the process with a malformed MQTT PUBLISH packet. Protocol::MQTT::read subtracts a user-controlled Topic Length from the packet's Remaining Length without first checking the bounds, then passes the negative result to memcpy as a huge unsigned size. No authentication or user interaction is required when remote attackers can supply a QoS 0 PUBLISH packet to the MQTT parser; the vendor establishes a process crash but states that precise code execution is not practical.

CVSS severity8.8
High
EPSS probability0.73%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Integer underflow in AIS-catcher before 0.64 allows remote attackers to crash the process with a malformed MQTT PUBLISH packet. Protocol::MQTT::read subtracts a user-controlled Topic Length from the packet's Remaining Length without first checking the bounds, then passes the negative result to memcpy as a huge unsigned size. No authentication or user interaction is required when remote attackers can supply a QoS 0 PUBLISH packet to the MQTT parser; the vendor establishes a process crash but states that precise code execution is not practical.

The record

CVE
CVE-2025-66217
Published
Nov 29, 2025
Updated
Dec 1, 2025
Vendor
jvde-github
Product
AIS-catcher
Classifications
CWE-191, CWE-122, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 29, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 1, 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?

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

  1. Affected versionversion=< 0.64

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

jvde-github · AIS-catcherversion=< 0.64

Published CVSS scores

8.8GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
7.5NIST NVDCVSS: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-191Integer Underflow (Wrap or Wraparound)
CWE-122Heap-based Buffer Overflow
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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