High7.5Apache Software Foundation

High [CVE-2025-66168 +1] Apache ActiveMQ: Integer Overflow or Wraparound vulnerability in Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT.

This high-severity Apache Software Foundation advisory covers CVE-2025-66168 and CVE-2026-40046 affecting Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT.

CVE-2026-40046 Published Apr 9, 2026Updated by vendor Jun 17, 2026

CVE-2025-66168 CVE-2026-40046

Affected products & platforms

Apache Software FoundationMessagingActiveMQ

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Summary

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.

Affected versions

6.0.0 through 6.2.4
6.0.0 through 6.2.4.

Official advisory · high-confidence parse· fetched 2 months ago·verify at source

Fixed versions

6.2.4
5.19.x
5.19.2
5.19.5

Official advisory · high-confidence parse· fetched 2 months ago·verify at source

Mitigation

Upgrade to a fixed release: 6.2.4, 5.19.x, 5.19.2, 5.19.5. That is the remediation for this advisory.

The vendor advisory may list additional interim mitigations or workarounds not captured here — review it before change work.

Official advisory · high-confidence parse· fetched 2 months ago·verify at source

Sources

Official and corroborating records used to build this advisory.

NVD discovery recordNVD
Independent discovery and scoring cross-reference. Vendor remediation guidance takes precedence. Discovered from the machine-readable feed https://services.nvd.nist.gov/rest/json/cves/2.0; this link opens the NVD record for CVE-2025-66168 instead of the raw feed document.
NIST National Vulnerability Database

Cross-references

Validate CVE metadata against the authoritative registries.

Official resources

ASF Security — reporting & CVE process
Official documentation
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Apache project downloads (fixed releases)
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Official ASF download tree — fetch the fixed release named in this advisory from the project's directory.

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