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Public proof of conceptFix available

CVE-2025-27533

A public proof of concept exists; no exploitation attested.

  • Published2025-05-07
  • Fixed in6.1.6 · 5.18.7 · 5.17.7 · 5.16.8
  • WeaknessCWE-789

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2025-05-0709:15CVE publishedNVD
  2. 2025-05-09Exploit-DB entryExploit-DB

Versions per branch

NVD · OSV
Apache activemq
BranchAffectedFixed in
6.x≥ 6.0.0, < 6.1.66.1.6
5.18≥ 5.18.0, < 5.18.75.18.7
5.17≥ 5.17.0, < 5.17.75.17.7
5.16≥ 5.16.0, < 5.16.85.16.8
5.16< 5.16.85.16.8

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As apache, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • Apache Software Foundation Apache ActiveMQother versions: not affected
    Affected
    • ≥ 6.0.0, < 6.1.6fixed in 6.1.6semver
    • ≥ 5.18.0, < 5.18.7fixed in 5.18.7semver
    • ≥ 5.17.0, < 5.17.7fixed in 5.17.7semver
    • ≥ 5.16.0, < 5.16.8fixed in 5.16.8semver

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2025-05-07

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • activemqUbuntu:Pro:22.04:LTSall versions · no fixed version listed
  • activemqUbuntu:Pro:20.04:LTSall versions · no fixed version listed
  • activemqUbuntu:Pro:18.04:LTSall versions · no fixed version listed
  • activemqUbuntu:Pro:16.04:LTSall versions · no fixed version listed
  • activemqUbuntu:26.10all versions · no fixed version listed
  • activemqUbuntu:26.04:LTSall versions · no fixed version listed
  • activemqUbuntu:25.10all versions · no fixed version listed
  • activemqUbuntu:24.04:LTSall versions · no fixed version listed

31 more package ranges on OSV.dev

Vendor advisories

  • CVE-2025-27533 Red Hat Product Security1 product fixed · 5 known affected

    ActiveMQ: ActiveMQ: Unvalidated Buffer Size Allocation

    activemq-openwire-legacy as a component of A-MQ Clients 2 · activemq-openwire-legacy as a component of Red Hat Data Grid 8 · activemq-openwire-legacy as a component of Red Hat Fuse 7 · +2 more

  • RHSA-2025:17567 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat AMQ Broker 7.13.2 release and security update

Full record on NVD

Fix

  1. Update Apache activemq to 6.1.6 · 5.18.7 · 5.17.7 · 5.16.8
  2. Vendor fix Red Hat Product Security RHSA-2025:17567 · 1 productBefore applying the update, back up your existing installation, including all applications, configuration files, databases and database settings. The References section of this erratum contains a download link (you must log in to download the update).
  3. No fix available, says the vendor Red Hat Product Security CVE-2025-27533 · 5 productsFix deferred

Advisories and patches

Detection

read 2026-11-01 01:02 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
EDB-52288
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 4.0 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:A/V:D/RE:M/U:Red
Published
2025-05-07
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-whxr-3p84-rf3c

Frequently asked questions

What is CVE-2025-27533?

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.

Is CVE-2025-27533 actively exploited?

Active exploitation of CVE-2025-27533 has not been confirmed. Its EPSS score was 9.1% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2025-27533?

CVE-2025-27533 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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