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CVE-2026-40466: Improper Input Validation, Improper Control of Generation of Code ('Code Injection') vulnerability in Apache A

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HIGH 8.8WATCHLISTUPGRADEUPGRADE

CVE-2026-40466 is a high-severity flaw (CVSS 8.8) affecting activemq, activemq broker. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

  • High severity
  • EPSS top 8%: very likely to be exploited
  • On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score8.8 (High)
Attack vectorNetwork (remote)
Attack complexityLow
Privileges neededLow
User interactionNone
EPSS exploit chance4.8% (top 8%)
CISA exploited listNo
WeaknessCWE-20, CWE-94
Published2026-04-24
Last modified2026-10-26
Publisher (CNA): Apache Software Foundation · Vendor: apache

Share: LinkedIn · X · Reddit

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

apache activemq UPGRADE
Affected: < 5.19.6 · >= 6.0.0 and < 6.2.5
Fixed in: 5.19.6, 6.2.5
Safe to downgrade to: a release before 6.0.0
1. Check installed version
apt-cache policy activemq || rpm -q activemq || activemq --version
2. UPGRADE to 5.19.6 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade activemq
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade activemq
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
3. If no update is available yet, DOWNGRADE to a release before 6.0.0 (Debian / Ubuntu)
apt-cache madison activemq sudo apt install activemq=<VERSION_BEFORE_6.0.0> sudo apt-mark hold activemq
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list activemq sudo dnf downgrade activemq-<VERSION_BEFORE_6.0.0> sudo dnf versionlock add activemq
Downgrade risk
Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.
After downgrade
Restart the service, and keep the package held until a fixed release ships.
apache activemq broker UPGRADE
Affected: < 5.19.6 · >= 6.0.0 and < 6.2.5
Fixed in: 5.19.6, 6.2.5
Safe to downgrade to: a release before 6.0.0
1. Check installed version
apt-cache policy activemq-broker || rpm -q activemq-broker || activemq-broker --version
2. UPGRADE to 5.19.6 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade activemq-broker
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade activemq-broker
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
3. If no update is available yet, DOWNGRADE to a release before 6.0.0 (Debian / Ubuntu)
apt-cache madison activemq-broker sudo apt install activemq-broker=<VERSION_BEFORE_6.0.0> sudo apt-mark hold activemq-broker
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list activemq-broker sudo dnf downgrade activemq-broker-<VERSION_BEFORE_6.0.0> sudo dnf versionlock add activemq-broker
Downgrade risk
Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.
After downgrade
Restart the service, and keep the package held until a fixed release ships.

Exact fixes by distribution

Maven · org.apache.activemq:apache-activemq · FIXED · 5.19.6 · vulnerable: < 5.19.6 · source
Set org.apache.activemq:apache-activemq to 5.19.6 or later in pom.xml or build.gradle, then rebuild and redeploy.
Maven · org.apache.activemq:activemq-all · FIXED · 5.19.6 · vulnerable: < 5.19.6 · source
Set org.apache.activemq:activemq-all to 5.19.6 or later in pom.xml or build.gradle, then rebuild and redeploy.
Maven · org.apache.activemq:activemq-broker · FIXED · 5.19.6 · vulnerable: < 5.19.6 · source
Set org.apache.activemq:activemq-broker to 5.19.6 or later in pom.xml or build.gradle, then rebuild and redeploy.
Debian 12 · activemq · NO FIX YET
Debian 13 · activemq · NO FIX YET
RHEL 8 · log4j:2/log4j · NOT AFFECTED
RHEL 9 · log4j · NOT AFFECTED

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-40466?

activemq: upgrade to 5.19.6, 6.2.5; activemq broker: upgrade to 5.19.6, 6.2.5. Exact commands for each OS are on this page.

Is CVE-2026-40466 being exploited?

CVE-2026-40466 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-40466 affect?

CVE-2026-40466 affects activemq, activemq broker. Severity is high (CVSS 8.8). 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

How urgent is CVE-2026-40466?

Priority 59/100. High severity; EPSS top 8%: very likely to be exploited; On your watchlist

Software pages

Apache ActiveMQ vulnerabilities

Related CVEs

References

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