How severe is CVE-2026-40466?

CVE-2026-40466 has a CVSS score of 8.8/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-40466?

CVE-2026-40466 affects the following packages: org.apache.activemq:apache-activemq (Maven), org.apache.activemq:activemq-all (Maven), org.apache.activemq:activemq-broker (Maven), org.apache.activemq:apache-activemq (Maven), org.apache.activemq:activemq-all (Maven), org.apache.activemq:activemq-broker (Maven). Ecosystems affected: Maven.

How do I fix CVE-2026-40466?

Update org.apache.activemq:apache-activemq to 5.19.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40466 is resolved across your whole dependency graph.

How do I detect CVE-2026-40466 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.activemq:apache-activemq, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-40466 if there is no patch (or I can't update yet)?

Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Is CVE-2026-40466 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-40466 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-40466?

CVE-2026-40466 has an EPSS (Exploit Prediction Scoring System) score of 4.8%, placing it in the 92th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-40466?

CVE-2026-40466 is classified as Improper Input Validation (CWE-20), Code Injection (CWE-94). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

Is there exploit tooling available for CVE-2026-40466?

A Nuclei detection template exists for CVE-2026-40466, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2026-40466 published, and has it been updated?

CVE-2026-40466 was published on April 24, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

HIGH severity

CVE-2026-40466 — apache-activemq

HIGH

CVE-2026-40466 is a high-severity (CVSS 8.8) Improper Input Validation vulnerability in org.apache.activemq:apache-activemq. A fix is available for org.apache.activemq:apache-activemq — see the affected versions and patch details below.

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

Also known asBIT-activemq-2026-40466GHSA-w3w2-mpp5-92gm

Published

Apr 24, 2026

Updated

Oct 28, 2026

Affected

6 pkgs

Patched

6 / 6

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-40466.

EPSS Exploitation Probability

via FIRST.org ↗

4.8%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs92th percentile — riskier than 92% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

6 pkgs affected

☕org.apache.activemq:apache-activemq☕org.apache.activemq:activemq-all☕org.apache.activemq:activemq-broker☕org.apache.activemq:apache-activemq☕org.apache.activemq:activemq-all☕org.apache.activemq:activemq-broker

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

6 total 6 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.apache.activemq:apache-activemq`	all versions	5.19.6`org.apache.activemq:apache-activemq:5.19.6`
☕Maven	`org.apache.activemq:activemq-all`	all versions	5.19.6`org.apache.activemq:activemq-all:5.19.6`
☕Maven	`org.apache.activemq:activemq-broker`	all versions	5.19.6`org.apache.activemq:activemq-broker:5.19.6`
☕Maven	`org.apache.activemq:apache-activemq`	≥ 6.0.0&&< 6.2.5	6.2.5`org.apache.activemq:apache-activemq:6.2.5`
☕Maven	`org.apache.activemq:activemq-all`	≥ 6.0.0&&< 6.2.5	6.2.5`org.apache.activemq:activemq-all:6.2.5`
☕Maven	`org.apache.activemq:activemq-broker`	≥ 6.0.0&&< 6.2.5	6.2.5`org.apache.activemq:activemq-broker:6.2.5`

Affected Products

2 products · 4 configurations

Application

activemqapache

≥ 6.0.0 && < 6.2.5

range

Application

activemq brokerapache

≥ 6.0.0 && < 6.2.5

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.activemq:apache-activemq, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.activemq:apache-activemq to 5.19.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40466 is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

How to detect CVE-2026-40466

A community-maintained Nuclei template exists for this CVE. You can scan for it directly:

nuclei -id cve-2026-40466 -u https://target

Template: Apache ActiveMQ - Remote Code Execution via HTTP Discovery Transport Bypass
Severity: high
Impact: Authenticated attackers can execute arbitrary code on the broker JVM, potentially leading to full system compromise.
Remediation: Attacker must be authenticated and activemq-http module must be on classpath.

Template by ProjectDiscovery nuclei-templates (DhiyaneshDk), MIT licensed. View the full template. Scan only systems you are authorised to test.

Frequently Asked Questions

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 brokerConfi

O3 Security · Impact-Aware SCA

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Find it across Maven, including transitive dependencies.

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CVSS Score

8.8/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Raw vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CWE Classification

CWE-20Improper Input Validation CWE-94Code Injection

Weaponization

OpenSSF Scorecard

Package health score

activemq

6.9/10

Code-Review10/10

Maintained10/10

Branch-ProtectionN/A

Assessed Nov 9, 2026

Timeline

Disclosed

Apr 24, 2026

Last updated

Oct 28, 2026

Identifiers

CVE-2026-40466

GHSA-w3w2-mpp5-92gm

BIT-activemq-2026-40466

References

Advisoryaccess.redhat.com · CVE 2026 40466 Advisoryactivemq.apache.org · CVE 2026 34197 announcement.txt Advisorygithub.com · CVE 2026 40466.json Advisorynvd.nist.gov · CVE 2026 40466 Reportbugzilla.redhat.com · show bug.cgi Webrepo.maven.apache.org · maven2 Websecurity.access.redhat.com · cve 2026 40466.json Packagegithub.com · activemq

Related vulnerabilities

This CVE is high severity; 7 of 8 other CVEs affecting apache-activemq are rated as high or higher (top: high).

CVE-2026-50734CVE-2026-50750CVE-2026-53917CVE-2026-49877CVE-2026-49434CVE-2026-52760CVE-2026-54475CVE-2026-49432

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 28, 2026

CVE-2026-40466 — apache-activemq

Exploitation Status

No confirmed exploitation observed yet

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

How to detect CVE-2026-40466

Frequently Asked Questions

Is CVE-2026-40466 in your dependencies?