CVE-2026-40046

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

7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

0.4% chance of exploitation in the next 30 days; higher than 31% of CVEs (scores of 2026-10-25)

CWE

CWE-190

Published

2026-04-09

Modified

2026-10-26

Record from

the NVD, synced 2026-10-26

Packages (OSV)

References

• https://activemq.apache.org/security-advisories.data/CVE-2026-40046-announcement.txt
• https://lists.apache.org/thread/zdntj5rcgjjzrpow84o339lzldy68zrg
• https://www.cve.org/CVERecord?id=CVE-2025-66168

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