Bug 2444356 (CVE-2025-66168)

Summary: CVE-2025-66168 org.apache.activemq/apache-activemq: org.apache.activemq/activemq-all: org.apache.activemq/activemq-mqtt: Apache ActiveMQ: Unexpected behavior due to integer overflow in MQTT packet decoding
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: asoldano, bbaranow, bmaxwell, brian.stansberry, darran.lofthouse, dosoudil, fjuma, gmalinko, istudens, ivassile, iweiss, janstey, mosmerov, msvehla, nwallace, pberan, pdelbell, pesilva, pjindal, pmackay, rstancel, rstepani, smaestri, tom.jenkinson
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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An integer overflow flaw has been discovered in Apache ActiveMQ. 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.
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Description OSIDB Bzimport 2026-03-04 10:01:47 UTC 
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.