CVE-2026-40046

EUVD-2026-20956

09.04.2026, 17:16

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.

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
apache	CNA	UNKNOWN				---

Base Score

CVSS 3.x

EPSS Score

Percentile: Unknown

Early Detection

Affected products identified ahead of NVD analysis through intelligence sources.

Vendor	Product	Version	Source
apache	activemq	6.0.0 ≤ 𝑥 < 6.2.4	CNA

Debian Releases

Debian Product

Codename

activemq

bookworm	5.17.2+dfsg-2+deb12u1 fixed
bookworm (security)	5.17.2+dfsg-2+deb12u1 fixed
bullseye	5.16.1-1 fixed
bullseye (security)	5.16.1-1+deb11u2 fixed
sid	5.17.6+dfsg-2 fixed
trixie	5.17.6+dfsg-2 fixed

Common Weakness Enumeration

CWE-190 - Integer Overflow or Wraparound
The software performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control.

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