CVE-2025-27533
HIGHEPSS 95th pctlDescription
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
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Exploit Intelligence
High risk: more likely to be exploited than 95% of all known CVEs.
References
Related Vulnerabilities
Other CWE-789 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2022-30522 | High | 7.5 | 90% | - | Fix |
| CVE-2026-49975 | High | 7.5 | 28% | - | Fix |
| CVE-2017-7651 | High | 7.5 | 5.3% | - | Fix |
| CVE-2021-31811 | Medium | 5.5 | 3.4% | - | - |
| CVE-2021-27906 | Medium | 5.5 | 3.3% | - | Fix |
| CVE-2024-43484 | High | 7.5 | 2.9% | - | Fix |
Common questions
How do I fix CVE-2025-27533?
Upgrade activemq on debian 11 to 5.16.1-1+deb11u2 or later.
Is CVE-2025-27533 being actively exploited?
Not that we know of. CVE-2025-27533 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 8.6% is the estimated probability that it will be exploited in the next 30 days. That is higher than 95% of all scored CVEs.
How severe is CVE-2025-27533?
CVE-2025-27533 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2025-27533 affect?
Published advisories record a fix for activemq (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2025-27533
Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-11-03.