CVE-2026-66257
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk25th percentile - higher than 25% of all known CVEs
Summary
A pre-authentication attacker could leverage unbounded symbol value caching to cause resource exhaustion leading to denial of service. This issue affects Apache Qpid Proton-J through 0.34.1. Users are recommended to upgrade to version 0.35.0, which fixes the issue.
Risk Assessment
The vulnerability could allow an unauthenticated attacker to exhaust memory or other resources, leading to service unavailability.
Recommendation
Upgrade Apache Qpid Proton-J to version 0.35.0 or later, which contains the fix.
Other vulnerabilities in Apache Qpid Proton-J
See all- CVE-2026-66277Medium
In Apache Qpid Proton-J through 0.34.1, it was not possible to govern the maximum number of transfer frames per incoming delivery, enabling an authenticated attacker to cause excessive resource usage and potential denial of service. The issue is fixed in version 0.35.0.
- CVE-2026-66276Medium
An authenticated attacker can craft a disposition frame with large or illegal ranges causing excessive CPU usage due to naive range handling, leading to denial of service. This issue affects Apache Qpid Proton-J through 0.34.1.
- CVE-2026-66275Medium
An authenticated attacker could exceed the session flow control incoming window potentially leading to denial of service. This issue affects Apache Qpid Proton-J through 0.34.1. Users are recommended to upgrade to version 0.35.0, which fixes the issue.
- CVE-2026-66274High
A pre-authentication attacker could leverage type nesting to cause a StackOverflowError potentially leading to denial of service. Affects Apache Qpid Proton-J through 0.34.1.
- CVE-2026-66273High
A 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-J through 0.34.1. Users are recommended to upgrade to version 0.35.0, which fixes the issue.
Original NVD description (English source)
A pre-authentication attacker could leverage unbounded symbol value caching to cause resource exhaustion leading to denial of service. This issue affects Apache Qpid Proton-J: through 0.34.1. Users are recommended to upgrade to version 0.35.0, which fixes the issue.

