High Input validation

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 Apr 24, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: apache

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

Detection templates (Nuclei) · 1

How the score was calculated

Public exploit/PoC (nuclei)+4
EPSS 4.1% (30-day exploitation probability)+14
Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

4.11%

ahead of 91% of scored CVEs · Oct 14, 2026

Affects

Apache Software Foundation

Apache ActiveMQ and 2 more

CVSS base

8.8

High · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Apache Software Foundation Apache ActiveMQ, Apache Software Foundation Apache ActiveMQ All, Apache Software Foundation Apache ActiveMQ Broker).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
EPSS ahead of 91% of scored CVEs: prioritize it in the patch queue.
Search available logs for exploit probes matching the vulnerability class (input validation), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Apache Software Foundation	Apache ActiveMQ	< 5.19.6≥ 6.0.0 and < 6.2.5	Vulnerable	NIST National Vulnerability Database
Apache Software Foundation	Apache ActiveMQ	< 5.19.6≥ 6.0.0 and < 6.2.5	Vulnerable	CVE Program (cve.org) e CISA ADP
Apache Software Foundation	Apache ActiveMQ All	< 5.19.6≥ 6.0.0 and < 6.2.5	Vulnerable	CVE Program (cve.org) e CISA ADP
Apache Software Foundation	Apache ActiveMQ Broker	< 5.19.6≥ 6.0.0 and < 6.2.5	Vulnerable	NIST National Vulnerability Database
Apache Software Foundation	Apache ActiveMQ Broker	< 5.19.6≥ 6.0.0 and < 6.2.5	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

Low

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
8.8	CVSS 3.1	High	2.8	5.9	134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database
8.8	CVSS 3.1	High	2.8	5.9	0b0ca135-0b70-47e7-9f44-1890c2a1c46c via NIST National Vulnerability Database
8.8	CVSS 3.1	High	—	—	CISA-ADP via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: 134c704f-9b21-4f2e-91b3-4a467353bcc0)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-20 · Improper Input Validation

Other CVEs with this weakness →

Public exploits, PoCs and detection templates

Public code that demonstrates or tests the flaw raises the odds of mass exploitation — and Nuclei templates help find vulnerable assets in your environment.

Detection templates (Nuclei)

Apache ActiveMQ - Remote Code Execution via HTTP Discovery Transport Bypass

Warning: public PoCs are sometimes disguised malware. Use them only for authorized testing in an isolated environment. This portal does not host exploit code — it only points to the sources.

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 4.11%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).

web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

2026
Affected products added · apache software foundation/apache activemq broker, apache software foundation/apache activemq all, apache software found
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
CVSS changed · 8.8
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Modified
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Apr 24, 2026 · apache

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

4 on the record

activemq.apache.org/security-advisories.data/CVE-2026-34197-announcement.txt
Not Applicable, vendor-advisory, NIST National Vulnerability Database
access.redhat.com/security/cve/CVE-2026-40466
NIST National Vulnerability Database
security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40466.json
NIST National Vulnerability Database
bugzilla.redhat.com/show_bug.cgi
NIST National Vulnerability Database

Elsewhere on this site

Apache Software Foundation
every CVE for this vendor

Input validation
same class

CWE-20
other pages naming this weakness

Related CVEs (same products)

High CVE-2026-74761 Apache ActiveMQ Broker, Apache ActiveMQ All, Apache ActiveMQ: Spoofing of RemoveSubscription clientId Sep 9, 2026
High CVE-2026-59878 Apache ActiveMQ AMQP, Apache ActiveMQ, Apache ActiveMQ All: AMQP NIO negative frame size validation bypass leading to DoS Jul 28, 2026
Medium CVE-2026-61487 Apache ActiveMQ Broker, Apache ActiveMQ All, Apache ActiveMQ: Authorization bypass via temporary composite destinations Jul 28, 2026
High CVE-2026-54475 Apache ActiveMQ Broker, Apache ActiveMQ All, Apache ActiveMQ: Temporary destination ownership takeover Jun 30, 2026
High CVE-2026-53917 Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ Client, Apache ActiveMQ Broker: Unbounded memory allocation in OpenWire property unmarshalling Jun 30, 2026
High CVE-2026-53916 Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ Stomp: Unbounded header buffer in STOMP NIO codec Jun 30, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No fixed version, patch or mitigation documented.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-40466 is "Apache ActiveMQ Broker, Apache ActiveMQ All, Apache ActiveMQ: Possible bypass of CVE-2026-34197 via HTTP discovery second-stage URI", rated High. It affects Apache ActiveMQ (Apache Software Foundation); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 8.8 describes technical severity. EPSS 4.11% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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