CVE-2026-67552 Apache Qpid Proton Dotnet: Unbounded type nesting can lead to pre-authentication stackoverflow

High 7.5 Published 5 Aug 2026 Updated 6 Aug 2026

A pre-authentication attacker can cause a stack overflow and denial of service via unbounded type nesting in the Apache Qpid Proton Dotnet library.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-67552?

CVE-2026-67552 is a high-severity denial of service vulnerability in Apache Qpid Proton Dotnet, published on 5 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A pre-authentication attacker could leverage type nesting to cause a StackOverflowError potentially leading to 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

Weakness: CWE-674

Which versions are affected by CVE-2026-67552?

It affects 1 product.

Products include Apache Qpid Proton-Dotnet.

How do I fix CVE-2026-67552?

No fix has been published for CVE-2026-67552 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-67552 being exploited?

There is no known exploitation of CVE-2026-67552 in the wild and no public exploit code.

Sources

Also known as GHSA-qwm2-w9f2-j6cg.