How severe is CVE-2026-50734?

CVE-2026-50734 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-50734?

CVE-2026-50734 affects the following packages: org.apache.activemq:activemq-client (Maven), org.apache.activemq:activemq-client (Maven), org.apache.activemq:apache-activemq (Maven), org.apache.activemq:apache-activemq (Maven), org.apache.activemq:activemq-all (Maven), org.apache.activemq:activemq-all (Maven). Ecosystems affected: Maven.

How do I fix CVE-2026-50734?

Update org.apache.activemq:activemq-client to 5.19.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-50734 is resolved across your whole dependency graph.

How do I detect CVE-2026-50734 in my Maven dependencies?

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

How do I mitigate CVE-2026-50734 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2026-50734 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-50734 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-2026-50734?

CVE-2026-50734 has an EPSS (Exploit Prediction Scoring System) score of 0.7%, placing it in the 55th 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-2026-50734?

CVE-2026-50734 is classified as CWE-789 (CWE-789). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-50734 published, and has it been updated?

CVE-2026-50734 was published on June 30, 2026 and was last updated on November 4, 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-2026-50734 — activemq-client

HIGHFix: apache/activemq#2080

CVE-2026-50734 is a high-severity (CVSS 7.5) CWE-789 vulnerability in org.apache.activemq:activemq-client. A fix is available for org.apache.activemq:activemq-client — see the affected versions and patch details below.

Apache ActiveMQ Client, Apache ActiveMQ, Apache ActiveMQ All: Pre-authentication OpenWire memory-allocation DoS during wire format negotiation

Also known asBIT-activemq-2026-50734GHSA-7259-vf48-52q3

Published

Jun 30, 2026

Updated

Nov 4, 2026

Affected

6 pkgs

Patched

6 / 6

Exploits

None indexed

Exploitation data as of Nov 4, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-50734.

EPSS Exploitation Probability

via FIRST.org ↗

0.7%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs55th percentile — riskier than 55% 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

6 pkgs affected

☕org.apache.activemq:activemq-client☕org.apache.activemq:activemq-client☕org.apache.activemq:apache-activemq☕org.apache.activemq:apache-activemq☕org.apache.activemq:activemq-all☕org.apache.activemq:activemq-all

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

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 Packages

6 total 6 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.apache.activemq:activemq-client`	all versions	5.19.8`org.apache.activemq:activemq-client:5.19.8`
☕Maven	`org.apache.activemq:activemq-client`	≥ 6.0.0&&< 6.2.7	6.2.7`org.apache.activemq:activemq-client:6.2.7`
☕Maven	`org.apache.activemq:apache-activemq`	all versions	5.19.8`org.apache.activemq:apache-activemq:5.19.8`
☕Maven	`org.apache.activemq:apache-activemq`	≥ 6.0.0&&< 6.2.7	6.2.7`org.apache.activemq:apache-activemq:6.2.7`
☕Maven	`org.apache.activemq:activemq-all`	all versions	5.19.8`org.apache.activemq:activemq-all:5.19.8`
☕Maven	`org.apache.activemq:activemq-all`	≥ 6.0.0&&< 6.2.7	6.2.7`org.apache.activemq:activemq-all:6.2.7`

Affected Products

1 product · 2 configurations

Application

activemqapache

≥ 6.0.0 && < 6.2.7

range

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:activemq-client, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.activemq:activemq-client to 5.19.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-50734 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

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

A flaw was found in Apache ActiveMQ Classic's OpenWire protocol handling. An unauthenticated remote attacker can crash the broker by sending a crafted WireFormatInfo frame with a malicious oversized value during pre-authentication protocol negotiation, causing an Out of Memory condition. Red Hat AMQ Broker is based on…

Workaround published by Red Hat

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Source: Red Hat security advisory for CVE-2026-50734 (CC BY 4.0)

Product	Fixed in	Advisory
AMQ Clients 2026.Q3	`artemis-core-client`	RHSA-2026:69459
Red Hat AMQ Broker 7.13.6	`activemq-client`	RHSA-2026:66545
Red Hat AMQ Broker 7.14.1	`activemq-client`	RHSA-2026:66488

Frequently Asked Questions

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.

O3 Security · Impact-Aware SCA

Is CVE-2026-50734 in your dependencies?

Find it across Maven, including transitive dependencies.

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CVSS Score

7.5/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CWE Classification

CWE-789CWE-789

Weaponization

No Nuclei template, Metasploit module or public proof-of-concept found.

Timeline

Disclosed

Jun 30, 2026

Last updated

Nov 4, 2026

Identifiers

CVE-2026-50734

GHSA-7259-vf48-52q3

BIT-activemq-2026-50734

References

Advisorygithub.com · CVE 2026 50734.json Advisorylists.apache.org · nxso951fnvf72qf9m475mpz4yf931xk0 Advisorynvd.nist.gov · CVE 2026 50734 Webopenwall.com Webrepo.maven.apache.org · maven2 Webgithub.com Webgithub.com · 42e2be75eddcece3cddacf8a73e6cad7db5aa626 Webgithub.com · 6fc46e520bac7d9763ba5762cc2de603f19ed517 Webgithub.com · e25f9b88898ef7cdfac9e855f4559a1ad0a6da12 Webgithub.com · activemq 5.19.8 Webgithub.com · activemq 6.2.7 Packagegithub.com · activemq

Related vulnerabilities

This CVE is high severity; 3 of 8 other CVEs affecting activemq-client are rated as high or higher (top: critical).

CVE-2026-53917CVE-2026-39304CVE-2026-33227CVE-2025-27533CVE-2023-46604CVE-2013-1879CVE-2013-3060CVE-2015-1830

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedNov 4, 2026

CVE-2026-50734 — activemq-client

Exploitation Status

No confirmed exploitation observed yet

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Fixing This On Your OS

Frequently Asked Questions

Is CVE-2026-50734 in your dependencies?