# CVE-2026-103582: Apache ActiveMQ NMS OpenWire Client Library: Unbounded/Unvalidated Length Fields in Apache.NMS.OpenWire Unmarshalling (DoS)

Status: published. Published: 2026-11-04. Updated: 2026-11-04.

Unbounded memory allocation and missing frame size validation in Apache NMS ActiveMQ (the .NET OpenWire client, package Apache.NMS.ActiveMQ) before 2.3.0.



The OpenWire unmarshalling code trusted the frame size and the length and count fields read from the network. It did not enforce a maximum frame size, and it did not check that decoded lengths fit within the frame being read. A malicious or compromised broker, or an attacker able to intercept and modify an unencrypted connection, could send a crafted OpenWire frame with an oversized or negative length. This could cause the client to attempt very large memory allocations, leading to excessive memory consumption, an OutOfMemoryException or an uncaught exception, and a denial of service of the client application.



Users are recommended to upgrade to version 2.3.0, which enforces a configurable maximum frame size and validates lengths against the size of the frame being read.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Apache Software Foundation / Apache ActiveMQ NMS OpenWire Client Library (Apache.NMS.ActiveMQ): ≥ 0; ≤ 2.2.0 (affected, semver). Source: CNA: apache

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-789

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://lists.apache.org/thread/vgn9pnsc7g9dhcctt804kd50tvs0ndq0 (CNA: apache; vendor-advisory)

- http://www.openwall.com/lists/oss-security/2026/11/03/15 (ADP: CVE)

- https://lists.apache.org/thread/vgn9pnsc7g9dhcctt804kd50tvs0ndq0 (security@apache.org)

## Provenance

- CNA: apache: https://www.cve.org/CVERecord?id=CVE-2026-103582; retrieved 2026-11-04; source updated 2026-11-04

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-103582; retrieved 2026-11-04; source updated 2026-11-04

Revision: 5d9d7c13075f7569a6f3b27263ce93de52ec94eeec9f3c7baca2ec8f9fe1bd47

Canonical: https://y2.dev/cve/CVE-2026-103582

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