CVE-2025-27533

Apache ActiveMQ: Unchecked buffer length can cause excessive memory allocation

HIGH
7.5
CVSS Score
Published: May 7, 2025 at 08:59 AM UTC
Updated: June 17, 2026 at 09:03 AM UTC
1 product affected across 1 vendorActiveMQ

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Severity
HIGH7.5
Exploit prediction
EPSS 9%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

5.16.0 ≤ v < 5.16.85.17.0 ≤ v < 5.17.75.18.0 ≤ v < 5.18.76.0.0 ≤ v < 6.1.65.16.05.17.05.18.06.0.0
Affected range stops below 5.16.8, so it looks safe — our inference, not a vendor statement
Affected range stops below 5.17.7, so it looks safe — our inference, not a vendor statement
Affected range stops below 5.18.7, so it looks safe — our inference, not a vendor statement
Affected range stops below 6.1.6, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (3)

Mailing ListThird Party Advisory
Source: af854a3a-2127-422b-91ae-364da2661108
http://www.openwall.com/lists/oss-security/2025/05/06/1
Source: af854a3a-2127-422b-91ae-364da2661108
https://lists.debian.org/debian-lts-announce/2025/06/msg00020.html

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-789

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