CVE-2026-40046: high-severity vulnerability in Apache ActiveMQ
Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT: Missing fix for CVE-2025-66168: MQTT control packet remaining length field is not properly validated
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.5epss 0.4%
Integer Overflow or Wraparound vulnerability in Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT.
The fix for "CVE-2025-66168: MQTT control packet remaining length field is not properly validated" was only applied to 5.19.2 (and future 5.19.x) releases but was missed for all 6.0.0+ versions.
This issue affects Apache ActiveMQ: from 6.0.0 before 6.2.4; Apache ActiveMQ All: from 6.0.0 before 6.2.4; Apache ActiveMQ MQTT: from 6.0.0 before 6.2.4.
Users are recommended to upgrade to version 6.2.4 or a 5.19.x version starting with 5.19.2 or later (currently latest is 5.19.5), which fixes the issue.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
Apache Software Foundation · Apache ActiveMQApache Software Foundation · Apache ActiveMQ AllApache Software Foundation · Apache ActiveMQ MQTTRelated CVEs — Apache ActiveMQ
In the same product, most dangerous first.
CVE-2023-46604CRITICALApache ActiveMQ, Apache ActiveMQ Legacy OpenWire Module: Unbounded deserialization causes ActiveMQ to be vulnerable to a remote code execution (RCE) attackEPSS 100.0%KEVCVE-2026-34197HIGHApache ActiveMQ Broker, Apache ActiveMQ All, Apache ActiveMQ: Authenticated users could perform RCE via Jolokia MBeansEPSS 98.3%KEVCVE-2022-41678—Apache ActiveMQ: Insufficient API restrictions on Jolokia allow authenticated users to perform RCEEPSS 85.8%CVE-2018-8006—CVE-2018-8006EPSS 55.7%CVE-2017-15709—CVE-2017-15709EPSS 22.8%CVE-2021-26117—ActiveMQ: LDAP-Authentication does not verify passwords on servers with anonymous bindEPSS 11.3%