How severe is CVE-2025-27533?

CVE-2025-27533 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2025-27533 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 8% (94th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-27533?

CVE-2025-27533 affects Apache Activemq. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-27533?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2025-27533 have an EU (EUVD) identifier?

Yes. CVE-2025-27533 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-13714.

When was CVE-2025-27533 published?

CVE-2025-27533 was published on 2025-05-07 and last updated on 2026-06-17.

CVE-2025-27533

CVE-2025-27533 is a high-severity vulnerability in Apache Activemq with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-789.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 6.9
EPSS exploit prediction: 8% (94th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-13714
Weakness: CWE-789
Affected product: Apache Activemq
Published: 2025-05-07
Last modified: 2026-06-17

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.

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.
How severe is CVE-2025-27533?: CVE-2025-27533 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2025-27533 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 8% (94th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-27533?: CVE-2025-27533 affects Apache Activemq. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-27533?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-27533 have an EU (EUVD) identifier?: Yes. CVE-2025-27533 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-13714.
When was CVE-2025-27533 published?: CVE-2025-27533 was published on 2025-05-07 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:apache:activemq:*:*:*:*:*:*:*:*

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