CVE-2025-27533: Apache ActiveMQ: Unchecked buffer length can cause excessive memory allocation
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.
Classification
CVE ID: CVE-2025-27533
CVSS Base Severity: MEDIUM
CVSS Base Score: 6.9
CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H/AU:Y/R:A/V:D/RE:M/U:Red
Problem Types
CWE-789 Memory Allocation with Excessive Size ValueAffected Products
Vendor: Apache Software Foundation
Product: Apache ActiveMQ
Exploit Prediction Scoring System (EPSS)
EPSS Score: 0.37% (probability of being exploited)
EPSS Percentile: 57.95% (scored less or equal to compared to others)
EPSS Date: 2025-06-05 (when was this score calculated)
References
https://nvd.nist.gov/vuln/detail/CVE-2025-27533https://lists.apache.org/thread/8hcm25vf7mchg4zbbhnlx2lc5bs705hg