Apache ActiveMQ does not properly validate the remaining length field which may lead to an overflow during the decoding of malformed packets. When this integer overflow occurs, ActiveMQ may incorrectly compute the total Remaining Length and subsequently misinterpret the payload as multiple MQTT control packets which makes the broker susceptible to unexpected behavior when interacting with non-compliant clients. This behavior violates the MQTT v3.1.1 specification, which restricts Remaining Length to a maximum of 4 bytes. The scenario occurs on established connections after the authentication process. Brokers that are not enabling mqtt transport connectors are not impacted.
This issue affects Apache ActiveMQ: before 5.19.2, 6.0.0 to 6.1.8, and 6.2.0
Users are recommended to upgrade to version 5.19.2, 6.1.9, or 6.2.1, which fixes the issue.
Metrics
Affected Vendors & Products
References
History
Thu, 05 Mar 2026 00:15:00 +0000
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| Weaknesses | CWE-130 | |
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threat_severity
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threat_severity
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Wed, 04 Mar 2026 21:15:00 +0000
| Type | Values Removed | Values Added |
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Apache
Apache activemq Apache activemq All Module Apache activemq Mqtt Module |
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Apache
Apache activemq Apache activemq All Module Apache activemq Mqtt Module |
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ssvc
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Wed, 04 Mar 2026 10:30:00 +0000
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Wed, 04 Mar 2026 09:15:00 +0000
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| Description | Apache ActiveMQ does not properly validate the remaining length field which may lead to an overflow during the decoding of malformed packets. When this integer overflow occurs, ActiveMQ may incorrectly compute the total Remaining Length and subsequently misinterpret the payload as multiple MQTT control packets which makes the broker susceptible to unexpected behavior when interacting with non-compliant clients. This behavior violates the MQTT v3.1.1 specification, which restricts Remaining Length to a maximum of 4 bytes. The scenario occurs on established connections after the authentication process. Brokers that are not enabling mqtt transport connectors are not impacted. This issue affects Apache ActiveMQ: before 5.19.2, 6.0.0 to 6.1.8, and 6.2.0 Users are recommended to upgrade to version 5.19.2, 6.1.9, or 6.2.1, which fixes the issue. | |
| Title | Apache ActiveMQ, Apache ActiveMQ All Module, Apache ActiveMQ MQTT Module: MQTT control packet remaining length field is not properly validated | |
| Weaknesses | CWE-190 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: apache
Published: 2026-03-04T08:45:00.932Z
Updated: 2026-03-04T20:28:45.825Z
Reserved: 2025-11-21T20:44:42.659Z
Link: CVE-2025-66168
Updated: 2026-03-04T09:15:41.385Z
Status : Awaiting Analysis
Published: 2026-03-04T09:15:54.757
Modified: 2026-03-04T18:08:05.730
Link: CVE-2025-66168