How severe is CVE-2021-26118?

CVE-2021-26118 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-26118?

CVE-2021-26118 affects the following packages: org.apache.activemq:artemis-openwire-protocol (Maven). Ecosystems affected: Maven.

How do I fix CVE-2021-26118?

Update org.apache.activemq:artemis-openwire-protocol to 2.16.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-26118 is resolved across your whole dependency graph.

How do I detect CVE-2021-26118 in my Maven dependencies?

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

How do I mitigate CVE-2021-26118 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2021-26118 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-26118 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-2021-26118?

CVE-2021-26118 has an EPSS (Exploit Prediction Scoring System) score of 3.9%, placing it in the 90th 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-2021-26118?

CVE-2021-26118 is classified as CWE-284 (CWE-284). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2021-26118 published, and has it been updated?

CVE-2021-26118 was published on January 27, 2021 and was last updated on October 24, 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-2021-26118 — artemis-openwire-protocol

HIGHFix: apache/activemq-artemis@e5566d5

CVE-2021-26118 is a high-severity (CVSS 7.5) CWE-284 vulnerability in org.apache.activemq:artemis-openwire-protocol. A fix is available for org.apache.activemq:artemis-openwire-protocol — see the affected versions and patch details below.

Apache ActiveMQ Artemis vulnerable to Improper Access Control

Also known asGHSA-q7fr-vqhq-v5xr

Published

Jan 27, 2021

Updated

Oct 24, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 1, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

3.9%probability of exploitation in next 30 days

Lower Risk-0.06%

Lower risk than most CVEs90th percentile — riskier than 90% 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

1 pkg affected

☕org.apache.activemq:artemis-openwire-protocol

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

While investigating ARTEMIS-2964 it was found that the creation of advisory messages in the OpenWire protocol head of Apache ActiveMQ Artemis 2.15.0 bypassed policy based access control for the entire session. Production of advisory messages was not subject to access control in error.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.apache.activemq:artemis-openwire-protocol`	all versions	2.16.0`org.apache.activemq:artemis-openwire-protocol:2.16.0`

Affected Products

2 products · 2 configurations

Application

artemisapache

1 version

2.15.0

Application

oncommand workflow automationnetapp

all

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:artemis-openwire-protocol, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.activemq:artemis-openwire-protocol to 2.16.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-26118 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant

Workaround published by Red Hat

If you are not using the openwire protocol, it can be disabled by removing it from the list of accepted protocols in the `broker.xml` ```xml <acceptor name="artemis">tcp://0.0.0.0:61616?tcpSendBufferSize=1048576;tcpReceiveBufferSize=1048576;amqpMinLargeMessageSize=102400;protocols=CORE,AMQP,STOMP,HORNETQ,MQTT;useEpoll=true;amqpCredits=1000;amqpLowCredits=300;amqpDuplicateDetection=true</acceptor> ```

Source: Red Hat security advisory for CVE-2021-26118 (CC BY 4.0)

RHSA-2020:5365Red Hat AMQ RHSA-2021:0417Red Hat AMQ 7.8.1