CVE-2026-67553: Apache Qpid Proton Dotnet: Incoming session flow control window can be exceeded

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-05 · updated 2026-10-24
Weakness: CWE-770

Description

An authenticated attacker could exceed the session flow control incoming window 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.

Affected products

Apache Software Foundation Apache Qpid Proton Dotnet: before 1.1.0 — fixed in 1.1.0

How to fix

Upgrade to a fixed version: Apache Software Foundation Apache Qpid Proton Dotnet 1.1.0. Check the vendor advisory for mitigations.

References

https://lists.apache.org/thread/hvsncmcbgjrn85crs909nf4y3dqqrywo
http://www.openwall.com/lists/oss-security/2026/08/04/24

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