CVE-2026-40046 | Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT: Missing fix for CVE-2025-66168: MQTT control packet remaining length field is not properly validated

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.

Published: 2026-04-09 Last update: 2026-04-13 Assigner: [email protected] Source: [email protected]
NVD Status：Awaiting Analysis，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-40046 is rated Moderate Risk (40.5/100): CVSS High severity, with low exploitation likelihood (EPSS 0.38%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-40046

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.05% 0.38% +0.33%
2 2026-04-15 0.02% 0.05% +0.03%
3 2026-04-10 — 0.02% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-40046

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2026-40046

GitHub Security Advisory for CVE-2026-40046

GHSA-xvqc-pp94-fmpx · Severity: medium · Ecosystem: maven — Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT vulnerable to Integer Overflow or Wraparound

OS Trackers for CVE-2026-40046

vendor priority summary link
debian unimportant CVE-2026-40046 unimportant priority: Debian including 1 source packages (activemq), 4 status rows across 4 suites (bookworm, bullseye, sid, trixie): resolved 4. https://security-tracker.debian.org/tracker/CVE-2026-40046
redhat medium — https://access.redhat.com/security/cve/CVE-2026-40046
ubuntu medium CVE-2026-40046 medium priority: Ubuntu including 1 source packages (activemq), 7 status rows across 7 suites (bionic, focal, jammy, noble, questing, upstream, xenial): needs-triage 6, not-affected 1. https://ubuntu.com/security/CVE-2026-40046

Affected software / configurations for CVE-2026-40046

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-40046

cvelogic Threat Intelligence