REDHAT-BUG-2494841: High severity Apache ActiveMQ Client vulnerability

Q: Who can exploit this issue?

An unauthenticated network attacker can exploit it if they can connect to an affected ActiveMQ broker and send a crafted WireFormatInfo frame during pre-authentication negotiation.

Q: Which deployments are affected?

Affected releases are Apache ActiveMQ Client, Apache ActiveMQ, and Apache ActiveMQ All versions before 5.19.8, and versions from 6.0.0 before 6.2.7.

Q: What is the impact of successful exploitation?

The broker may attempt an excessively large memory allocation, causing an out-of-memory condition and crashing the broker. This results in denial of service.

Q: What version should be deployed to remediate the issue?

Upgrade affected 5.x deployments to 5.19.8 or affected 6.x deployments to 6.2.7.

Published Jun 30, 2026

Updated

Memory Allocation with Excessive Size Value vulnerability in Apache ActiveMQ Client, Apache ActiveMQ, Apache ActiveMQ All.

An unauthenticated network attacker can cause a broker DoS by sending a crafted WireFormatInfo frame with a malicious large size value. The value is not validate and causes the broker to attempt allocation during pre-auth negotiation which can trigger OOM and crash the broker. This issue affects Apache ActiveMQ Client: before 5.19.8, from 6.0.0 before 6.2.7; Apache ActiveMQ: before 5.19.8, from 6.0.0 before 6.2.7; Apache ActiveMQ All: before 5.19.8, from 6.0.0 before 6.2.7.

Users are recommended to upgrade to version 6.2.7 or 5.19.8, which fixes the issue.

Affected Software

3 affected components

Apache ActiveMQ Client<5.19.8, >=6.0.0<6.2.7

Apache ActiveMQ<5.19.8, >=6.0.0<6.2.7

Apache ActiveMQ All<5.19.8, >=6.0.0<6.2.7

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade Apache ActiveMQ Client to a version that resolves this vulnerability.
Fixed in 6.2.7
Upgrade
Upgrade Apache ActiveMQ Client to a version that resolves this vulnerability.
Fixed in 5.19.8
Upgrade
Upgrade Apache ActiveMQ to a version that resolves this vulnerability.
Fixed in 6.2.7
Upgrade
Upgrade Apache ActiveMQ to a version that resolves this vulnerability.
Fixed in 5.19.8
Upgrade
Upgrade Apache ActiveMQ All to a version that resolves this vulnerability.
Fixed in 6.2.7
Upgrade
Upgrade Apache ActiveMQ All to a version that resolves this vulnerability.
Fixed in 5.19.8

Event History

Jun 30, 2026

Data Sourced

via Red Hat·11:01 AM

DescriptionSeverityAffected Software

Frequently Asked Questions

Who can exploit this issue?

An unauthenticated network attacker can exploit it if they can connect to an affected ActiveMQ broker and send a crafted WireFormatInfo frame during pre-authentication negotiation.

Which deployments are affected?

Affected releases are Apache ActiveMQ Client, Apache ActiveMQ, and Apache ActiveMQ All versions before 5.19.8, and versions from 6.0.0 before 6.2.7.

What is the impact of successful exploitation?

The broker may attempt an excessively large memory allocation, causing an out-of-memory condition and crashing the broker. This results in denial of service.

What version should be deployed to remediate the issue?

Upgrade affected 5.x deployments to 5.19.8 or affected 6.x deployments to 6.2.7.

REDHAT-BUG-2494841: High severity Apache ActiveMQ Client vulnerability

Affected Software

Remediation

Event History

Frequently Asked Questions

Who can exploit this issue?

Which deployments are affected?

What is the impact of successful exploitation?

What version should be deployed to remediate the issue?

Company

Resources

Contact

Frequently Asked Questions

Who can exploit this issue?

Which deployments are affected?

What is the impact of successful exploitation?

What version should be deployed to remediate the issue?