Skip to main content
VulnerabilityPublished Updated

CVE-2025-66168: Apache ActiveMQ · Integer Overflow or Wraparound

Affects Apache ActiveMQSource CVE Database V5

0
Compare

Mentioned vulnerabilities

Not known to be exploited · CVSS 5.4 Medium · fixed in 6.2.1 : update Apache ActiveMQ when convenient.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score
5.4Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.7% chance of exploitation in 30 days – higher than 56% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 6.2.1, 6.1.9, 5.19.2
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 4 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade Apache ActiveMQ and Apache ActiveMQ All Module and Apache ActiveMQ MQTT Module and Apache Software Foundation/org.apache.activemq:apache-activemq and Apache Software Foundation/org.apache.activemq:activemq-all and Apache Software Foundation/org.apache.activemq:activemq-mqtt to 6.2.1, 6.1.9 or 5.19.2; org.apache.activemq/activemq to 5.19.2.

Affected software

ProductAffectedFixed in
Apache Software FoundationApache ActiveMQAffected
  • >=6.2.0 <6.2.1
Fixed in
  • 6.2.1
Apache Software FoundationApache ActiveMQAffected
  • >=6.0.0 <6.1.9
Fixed in
  • 6.1.9
Apache Software FoundationApache ActiveMQAffected
  • <5.19.2
Fixed in
  • 5.19.2
Apache Software FoundationApache ActiveMQ All ModuleAffected
  • >=6.2.0 <6.2.1
Fixed in
  • 6.2.1
Apache Software FoundationApache ActiveMQ All ModuleAffected
  • >=6.0.0 <6.1.9
Fixed in
  • 6.1.9
Apache Software FoundationApache ActiveMQ All ModuleAffected
  • <5.19.2
Fixed in
  • 5.19.2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available. Users should upgrade Apache ActiveMQ to version 5.19.2, 6.1.9, or 6.2.1 or later to address this vulnerability. The advisory notes that users of 6.x should upgrade to 6.2.4 or later as the fix was missed in earlier 6.x releases. No additional mitigation steps are indicated beyond applying the official patches.

Description

WARNING: Users of 6.x should upgrade to 6.2.4 or later as the fix was missed in previous 6.x releases. See the  following for more details: https://activemq.apache.org/security-advisories.data/CVE-2026-40046-announcement.txt https://www.cve.org/CVERecord?id=CVE-2026-40046 Original Report: 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.

References

Community reviews

Loading reviews…