CVE-2025-27533

HIGH

Apache ActiveMQ 5.16.0-5.16.7, 5.17.0-5.17.6, 5.18.0-5.18.6 - Denial of Service via OpenWire Buffer Size Validation

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 2 public exploits for CVE-2025-27533. PoCs published by Abdualhadi khalifa, absholi7ly.

AI-analyzed exploit summary This exploit targets CVE-2025-27533, a DoS vulnerability in Apache ActiveMQ 6.1.6. It sends maliciously crafted packets with large buffer sizes to overwhelm the server, causing a denial of service.

Description

Memory Allocation with Excessive Size Value vulnerability in Apache ActiveMQ. During unmarshalling of OpenWire commands the size value of buffers was not properly validated which could lead to excessive memory allocation and be exploited to cause a denial of service (DoS) by depleting process memory, thereby affecting applications and services that rely on the availability of the ActiveMQ broker when not using mutual TLS connections. This issue affects Apache ActiveMQ: from 6.0.0 before 6.1.6, from 5.18.0 before 5.18.7, from 5.17.0 before 5.17.7, before 5.16.8. ActiveMQ 5.19.0 is not affected. Users are recommended to upgrade to version 6.1.6+, 5.19.0+, 5.18.7+, 5.17.7, or 5.16.8 or which fixes the issue. Existing users may implement mutual TLS to mitigate the risk on affected brokers.

Exploits (2)

exploitdb WORKING POC
by Abdualhadi khalifa · pythonremotemultiple
https://www.exploit-db.com/exploits/52288

This exploit targets CVE-2025-27533, a DoS vulnerability in Apache ActiveMQ 6.1.6. It sends maliciously crafted packets with large buffer sizes to overwhelm the server, causing a denial of service.

Classification
Working Poc 95%
Attack Type
Dos
Complexity
Moderate
Reliability
Reliable
Target: Apache ActiveMQ 6.1.6
No auth needed
Prerequisites: Network access to the target server · Open port for ActiveMQ (default: 61616)
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec WORKING POC 8 stars
by absholi7ly · poc
https://github.com/absholi7ly/CVE-2025-27533-Exploit-for-Apache-ActiveMQ

This is a functional DoS exploit for CVE-2025-27533 targeting Apache ActiveMQ. It sends maliciously crafted packets with large buffer sizes to trigger a denial-of-service condition.

Classification
Working Poc 95%
Attack Type
Dos
Complexity
Moderate
Reliability
Reliable
Target: Apache ActiveMQ
No auth needed
Prerequisites: Network access to the target ActiveMQ instance · Open port (default 61616 for OpenWire)
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (3)

Core 3

Scores

CVSS v3 7.5
EPSS 0.0225
EPSS Percentile 85.0%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-789
Status published
Products (3)
apache/activemq 5.16.0 - 5.16.8
org.apache.activemq/activemq-client 0 - 5.16.8Maven
org.apache.activemq/activemq-openwire-legacy 0 - 5.16.8Maven
Published May 07, 2025
Tracked Since Feb 18, 2026