Improper Input Validation, Improper Control of Generation of Code ('Code Injection')…
CVE-2026-40466 is a high-severity improper input validation vulnerability in Apache ActiveMQ Broker from Apache, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists versions 5.19.6, 6.2.5 as the first without the flaw, so updating Apache ActiveMQ Broker to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 4.78% chance of exploitation within 30 days, which is in the top 7.93% of all scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Apache ActiveMQ Broker to 5.19.6 or 6.2.5, whichever matches your release line, or a later version.
- Update Apache ActiveMQ All to 5.19.6 or 6.2.5, whichever matches your release line, or a later version.
- Update Apache ActiveMQ to 5.19.6 or 6.2.5, whichever matches your release line, or a later version.
- Read the advisory on activemq.apache.org for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apache | Apache ActiveMQ Broker | before 5.19.6; 6.0.0 up to, but not including, 6.2.5 | 5.19.6, 6.2.5 |
| Apache | Apache ActiveMQ All | before 5.19.6; 6.0.0 up to, but not including, 6.2.5 | 5.19.6, 6.2.5 |
| Apache | Apache ActiveMQ | before 5.19.6; 6.0.0 up to, but not including, 6.2.5 | 5.19.6, 6.2.5 |
| Red Hat | Red Hat AMQ Broker 7 | Not specified in the record | Not stated |
| Red Hat | Red Hat Data Grid 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9 | Not specified in the record | Not stated |
| Red Hat | Red Hat Fuse 7 | Not specified in the record | Not stated |
| Red Hat | Red Hat JBoss Enterprise Application Platform 7 | Not specified in the record | Not stated |
| Red Hat | Red Hat JBoss Enterprise Application Platform 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat JBoss Enterprise Application Platform Expansion Pack | Not specified in the record | Not stated |
| Apache | Activemq | before 5.19.6; 6.0.0 up to, but not including, 6.2.5 | 5.19.6, 6.2.5 |
| Apache | Activemq Broker | before 5.19.6; 6.0.0 up to, but not including, 6.2.5 | 5.19.6, 6.2.5 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.8 | High | CISA (ADP) |
| CVSS 3.1 | 8.8 | High | CNA |
Official 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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
How developers prevent this class of flaw
- Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build recognizers for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of allowing parser code to be scattered throughout the program, where it could be subject to errors or inconsistencies that create weaknesses.
- Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
- Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other references
Other vulnerabilities in Apache ActiveMQ Broker
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 8.8 High severity
Recent Improper Input Validation vulnerabilities
- 7.2 High severity
- 9.8 Critical severity
- 9.6 Critical severity
- 7.8 High severity
- 7.2 High severity
- 8.2 High severity
Spotted an error? Tell us.