CVE-2026-40466 | Apache ActiveMQ Broker, Apache ActiveMQ All, Apache ActiveMQ: Possible bypass of CVE-2026-34197 via HTTP discovery second-stage URI

Improper Input Validation, Improper Control of Generation of Code ('Code Injection') vulnerability in Apache ActiveMQ Broker, Apache ActiveMQ All, Apache ActiveMQ. An authenticated attacker may bypass the fix in CVE-2026-34197 by adding a connector using an HTTP Discovery transport via BrokerView.addNetworkConnector or BrokerView.addConnector through Jolokia if the activemq-http module is on the classpath. A malicious HTTP endpoint can return a VM transport through the HTTP URI which will bypass the validation added in CVE-2026-34197. The attacker can then use the VM transport's brokerConfig parameter to load a remote Spring XML application context using ResourceXmlApplicationContext. Because Spring's ResourceXmlApplicationContext instantiates all singleton beans before the BrokerService validates the configuration, arbitrary code execution occurs on the broker's JVM through bean factory methods such as Runtime.exec(). This issue affects Apache ActiveMQ Broker: before 5.19.6, from 6.0.0 before 6.2.5; Apache ActiveMQ All: before 5.19.6, from 6.0.0 before 6.2.5; Apache ActiveMQ: before 5.19.6, from 6.0.0 before 6.2.5. Users are recommended to upgrade to version 5.19.6 or 6.2.5, which fixes the issue.

Published: 2026-04-24 Last update: 2026-04-27 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2026-40466 is rated High Risk (70.8/100): CVSS High severity, with high exploitation likelihood (EPSS 18.01%, 95th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +2.22% over the last day, indicating growing attacker interest. Mandatory action: High exploitation likelihood—assess exposure and prioritize 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-2026-40466

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 2026-05-26 15.79% 18.01% +2.22%
2 2026-05-22 10.33% 15.79% +5.46%
3 2026-05-12 10.33%

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-40466

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:L)
A normal user session is enough; they don’t have to be admin.
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:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
2.8 5.9 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2026-40466

GitHub Security Advisory for CVE-2026-40466

GHSA-w3w2-mpp5-92gm · Severity: high · Ecosystem: maven — Apache ActiveMQ Vulnerable to Improper Input Validation and Code Injection

OS Trackers for CVE-2026-40466

vendor priority summary link
debian not yet assigned CVE-2026-40466 not yet assigned priority: Debian including 1 source packages (activemq), 4 status rows across 4 suites (bookworm, bullseye, sid, trixie): open 4. https://security-tracker.debian.org/tracker/CVE-2026-40466
ubuntu medium CVE-2026-40466 medium priority: Ubuntu including 1 source packages (activemq), 8 status rows across 8 suites (bionic, focal, jammy, noble, questing, resolute, upstream, xenial): needs-triage 8. https://ubuntu.com/security/CVE-2026-40466

Affected software / configurations for CVE-2026-40466

Vendor Product Version Raw CPE
apache activemq < 5.19.6 cpe:2.3:a:apache:activemq:*:*:*:*:*:*:*:*
apache activemq >= 6.0.0, < 6.2.5 cpe:2.3:a:apache:activemq:*:*:*:*:*:*:*:*
apache activemq_broker < 5.19.6 cpe:2.3:a:apache:activemq_broker:*:*:*:*:*:*:*:*
apache activemq_broker >= 6.0.0, < 6.2.5 cpe:2.3:a:apache:activemq_broker:*:*:*:*:*:*:*:*

References for CVE-2026-40466

cvelogic Threat Intelligence