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.
How to fix CVE-2025-27533
To remediate CVE-2025-27533, upgrade the affected package to a fixed version below.
- —upgrade to 5.16.8 or later
- —upgrade to 5.16.1-1+deb11u2 or later
- —upgrade to 5.16.1-1+deb11u2 or later
- —upgrade to 5.16.8 or later
- —upgrade to 5.16.8 or later
Is CVE-2025-27533 being exploited?
Moderate — EPSS is 8.5%. Track this CVE but it's not at the top of the prioritisation list.
Affected packages (5)
- >= 5.16.0, < 5.16.8, >= 5.17.0, < 5.17.7, >= 5.18.0, < 5.18.7, >= 6.0.0, < 6.1.6
- from 0, < 5.16.1-1+deb11u2
- from 0, < 5.16.1-1+deb11u2
- from 0, < 5.16.8
- from 0, < 5.16.8
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | 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 |
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |