CVE-2026-67591: Apache Qpid PROTONJ2

Medium severity, CVSS 6.5. EPSS: 0.7% chance of exploitation in the next 30 days.

An authenticated attacker could exceed the session flow control incoming window potentially leading to denial of service. This issue affects Apache Qpid ProtonJ2: through 1.1.0. Users are recommended to upgrade to version 1.2.0, which fixes the issue.

Affected products

• Apache Qpid PROTONJ2: before 1.2.0 (fixed in 1.2.0)

Published 2026-08-05. Last modified 2026-08-07.