---
id: CVE-2026-67551
title: >-
  pre-authentication attacker could leverage type size/count handling to cause
  excessive allocation leading to potential denial of service.


  This issue affects Apache Qpid Proton-Dotnet: through 1.0.0.


  Users are recommended to upgrade to …
summary: >-
  pre-authentication attacker could leverage type size/count handling to cause
  excessive allocation leading to potential denial of service.


  This issue affects Apache Qpid Proton-Dotnet: through 1.0.0.


  Users are recommended to upgrade to …
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-789
  - CWE-770
vendor: apache
product: qpid_proton-dotnet
affected:
  - qpid_proton-dotnet < 1.1.0
patched:
  - qpid_proton-dotnet 1.1.0
published: '2026-08-05'
updated: '2026-08-07'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-67551'
references:
  - url: 'https://lists.apache.org/thread/o566fhkrr3gg0lyzt24xwvz9w94oo6ro'
    label: security@apache.org
  - url: 'http://www.openwall.com/lists/oss-security/2026/08/04/22'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-67551.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-67551'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2511330'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-67551'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-67551'
  - url: 'https://access.redhat.com/errata/RHSA-2026:69459'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
epss: 0.00774
epssPercentile: 0.53867
ingestedAt: '2026-08-08T20:29:48.935Z'
---

## Overview

pre-authentication attacker could leverage type size/count handling to cause excessive allocation leading to potential denial of service.

This issue affects Apache Qpid Proton-Dotnet: through 1.0.0.

Users are recommended to upgrade to version 1.1.0, which fixes the issue.

## Affected

- `qpid_proton-dotnet < 1.1.0`

## Remediation

Upgrade past the affected range:

- `qpid_proton-dotnet 1.1.0`

## Vendor advisories

- **RHSA-2026:69459** · Red Hat · fixed in: AMQ Clients 2026.Q3 · released 2026-09-21 · [advisory](https://access.redhat.com/errata/RHSA-2026:69459)