CVE-2025-27533: CVE-2025-27533: Memory Allocation with Excessive Size Value vulnerability in Apache ActiveMQ. During unma…
apache · activemq · NVD published 2025-05-07 · posted 2025-05-09 · last modified 2026-06-17
What it is
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.
| Weakness | CWE-789 |
|---|---|
| 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/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 (source: [email protected]) |
| ATT&CK tactics | Impact |
Exploitation evidence
First exploit evidence seen: 2025-05-09 (earliest date across the sources below).
Exploited in the wild
No source on this site lists in-the-wild exploitation yet (CISA KEV, VulnCheck KEV).
Public exploit code
Exploit-DB
- EDB-52288: Apache ActiveMQ 6.1.6 - Denial of Service (DOS) (2025-05-09)
GitHub proof-of-concept repositories below quality bar
1 public repositories from 1 accounts, first seen 2025-05-09.
Verify before running: public PoCs can be malicious. Read the code and only run it in an isolated lab. A PoC means exploit code is public, not that this CVE is exploited in the wild.
Sources: Exploit-DB (OffSec) · nomi-sec/PoC-in-GitHub.
Defend the Chain
The attack chain for CVE-2025-27533 laid across the MITRE ATT&CK Enterprise tactics. Solid cards come from the MITRE CTID KEV mappings; dashed cards are inferred by CVERadar from the CWE or description. Correct defences are real ATT&CK mitigations for that technique.
Pick a red technique card on the board, then choose the defence that stops it.
Defend against T1499 Endpoint Denial of Service Inferred
Inferred from description keywords
How to fix it
Fixed versions
- apache activemq: upgrade to 5.16.8 or later (affected from 5.16.0)
- apache activemq: upgrade to 5.17.7 or later (affected from 5.17.0)
- apache activemq: upgrade to 5.18.7 or later (affected from 5.18.0)
- apache activemq: upgrade to 6.1.6 or later (affected from 6.0.0)
Derived from the NVD CPE configuration (versionEndExcluding / versionEndIncluding). Always confirm with the vendor advisory.
Vendor advisories and patches
- https://lists.apache.org/thread/8hcm25vf7mchg4zbbhnlx2lc5bs705hg (Mailing List, Vendor Advisory)
MITRE ATT&CK mitigations for this chain
- M1037 Filter Network Traffic (for T1499) : Leverage services provided by Content Delivery Networks (CDN) or providers specializing in DoS mitigations to filter traffic upstream from services. Filter boundary traffic by blocking source addresses sourcing the attack, blocking ports that are being targeted, or blocking protocols being used for transport. To defend
Detection Generic guidance
- Impact: Monitor service availability, unexpected encryption activity and mass file changes.
Response checklist Generic guidance
- Inventory: find every instance of the affected product and version (include internet-facing and forgotten ones).
- Patch or mitigate per the vendor advisory; if you cannot patch, remove internet exposure or apply the vendor workaround.
- Assume compromise if the system was exposed before patching: hunt for the indicators in the advisory and review logs back to the disclosure date.
- Rotate credentials and secrets stored on or used by the affected system if compromise cannot be ruled out.