CVE-2025-29953: Apache ActiveMQ NMS OpenWire Client: deserialization allowlist bypass

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-04-18 · updated 2026-06-17
Weakness: CWE-502

Description

Deserialization of Untrusted Data vulnerability in Apache ActiveMQ NMS OpenWire Client. This issue affects Apache ActiveMQ NMS OpenWire Client before 2.1.1 when performing connections to untrusted servers. Such servers could abuse the unbounded deserialization in the client to provide malicious responses that may eventually cause arbitrary code execution on the client. Version 2.1.0 introduced a allow/denylist feature to restrict deserialization, but this feature could be bypassed. The .NET team has deprecated the built-in .NET binary serialization feature starting with .NET 9 and suggests migrating away from binary serialization. The project is considering to follow suit and drop this part of the NMS API altogether. Users are recommended to upgrade to version 2.1.1, which fixes the issue. We also recommend to migrate away from relying on .NET binary serialization as a hardening method for the future.

Affected products

Apache Software Foundation Apache ActiveMQ NMS OpenWire Client: before 2.1.1 — fixed in 2.1.1

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache ActiveMQ NMS OpenWire Client 2.1.1. Check the vendor advisory for mitigations.

References

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