Security Digest · Vulnerability record
CVE-2025-29953: Apache ActiveMQ NMS OpenWire Client Deserialization of Untrusted Data vulnerability
Deserialization of Untrusted Data vulnerability in Apache ActiveMQ NMS OpenWire Client.
CVSS 9.8 Critical EPSS 2.1% · p81
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 2.1%, percentile 81: FIRST’s model estimates a 2.1% chance of exploitation activity in the next 30 days, higher than 81% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes
Apache.NMS.ActiveMQ(NuGet) < 2.1.1, fixed in 2.1.1. Check your lockfile, including transitive dependencies.
What it is
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.
From the GitHub advisory
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.
Weakness type: CWE-502.
Product: Apache.NMS.ActiveMQ (NuGet) · Assigned by: apache · Published: 2025-04-18
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| NuGet | Apache.NMS.ActiveMQ | < 2.1.1 | 2.1.1 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| Apache Software Foundation | Apache ActiveMQ NMS OpenWire Client | < 2.1.1 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| CISA-ADP | 3.1 | 9.8 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| GitHub | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
- FIRST EPSS (model of 2026-10-21): 2.09% probability of exploitation activity in the next 30 days; percentile 81.
Timeline
- — CVE record published by apache
- — GitHub-reviewed advisory GHSA-9g64-r942-fvmp published (critical)
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vendor and project advisories, patches
- lists.apache.org lists.apache.org
Vulnerability records
- GitHub Advisory GHSA-9g64-r942-fvmp github.com
- CVE.org record CVE-2025-29953 cve.org
- NVD entry CVE-2025-29953 nvd.nist.gov
Other references from the CVE record and advisory
- openwall.com openwall.com
- github.com github.com
- issues.apache.org issues.apache.org