What is CVE-2026-40046?

CVE-2026-40046 is a high-severity vulnerability in Apache Software Foundation Activemq, classified under Integer Overflow or Wraparound. CVSS score: 7.5/10. Published 2026-04-09.

How severe is CVE-2026-40046?

High severity. CVSS v3 base score is 7.5 out of 10.

Integer overflow in Apache Software Foundation Activemq

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.

Vulnerability class: Integer Overflow

EPSS: 0.004 (30.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Apache Software Foundation Activemq — versions 6.0.0
Apache Software Foundation Activemq All — versions 6.0.0
Apache Software Foundation Activemq Mqtt — versions 6.0.0

Weakness classification (CWE)

CWE-190 — Integer Overflow or Wraparound

References

security@apache.org (related)
security@apache.org (vendor-advisory)
security@apache.org (vendor-advisory)

Frequently asked questions

What is CVE-2026-40046?: CVE-2026-40046 is a high-severity vulnerability in Apache Software Foundation Activemq, classified under Integer Overflow or Wraparound. CVSS score: 7.5/10. Published 2026-04-09.
How severe is CVE-2026-40046?: High severity. CVSS v3 base score is 7.5 out of 10.