CVE-2026-67465 in Qpid Proton DotNet
Summary
by MITRE • 08/05/2026
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-Dotnet: through 1.0.0.
Users are recommended to upgrade to version 1.1.0, which fixes the issue.
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Analysis
by VulDB Data Team • 08/05/2026
The vulnerability described represents a critical resource exhaustion flaw affecting Apache Qpid Proton-Dotnet versions through 1.0.0, where attackers can exploit unbounded symbol value caching mechanisms to induce denial of service conditions. This pre-authentication attack vector allows remote adversaries to manipulate the system's memory management by leveraging the lack of proper bounds on symbol cache entries, ultimately leading to system resource exhaustion and operational disruption.
The technical implementation of this vulnerability stems from improper handling of symbol values within the proton-dotnet library's caching mechanism. When processing incoming messages or connections, the system maintains a cache of symbol values without implementing adequate size limitations or eviction policies. This design flaw creates an opportunity for attackers to continuously submit large numbers of unique symbol values, causing the cache to grow indefinitely until system resources are depleted. The vulnerability operates at the protocol level where symbol values are used for various internal operations including message routing and metadata handling.
From an operational impact perspective, this vulnerability exposes systems running affected versions of Apache Qpid Proton-Dotnet to significant availability risks. Once exploited, the denial of service condition can render messaging services completely inaccessible to legitimate users while consuming excessive memory resources and potentially causing system crashes or restarts. The pre-authentication nature means that no credentials or prior access are required to initiate the attack, making it particularly dangerous in production environments where such services may be exposed to untrusted networks.
The mitigation strategy involves upgrading to Apache Qpid Proton-Dotnet version 1.1.0, which implements proper bounds checking and cache eviction mechanisms for symbol values. This upgrade addresses the root cause by introducing maximum limits on cached symbol entries and implementing appropriate garbage collection policies. Organizations should also consider implementing network-level controls such as rate limiting and connection throttling to provide additional defense-in-depth measures while performing the upgrade process.
This vulnerability aligns with CWE-400, which specifically addresses "Uncontrolled Resource Consumption" in software systems, and demonstrates the importance of proper resource management in distributed messaging environments. The attack pattern corresponds to techniques described in the ATT&CK framework under the "Resource Exhaustion" tactic, where adversaries target system resources to disrupt service availability. Organizations should also consider implementing monitoring solutions to detect unusual cache growth patterns that might indicate exploitation attempts, ensuring comprehensive protection against similar vulnerabilities in other components of their messaging infrastructure.