CVE-2026-67554 in Qpid Proton Dotnet
Summary
by MITRE • 08/05/2026
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-Dotnet: through 1.0.0.
Users are recommended to upgrade to version 1.1.0, which fixes the issue.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 08/05/2026
The vulnerability described represents a denial of service condition within Apache Qpid Proton-Dotnet library versions through 1.0.0, where authenticated attackers can exploit improper handling of disposition frame ranges to consume excessive CPU resources. This flaw specifically targets the protocol implementation's approach to processing disposition frames, which are used in amqp messaging protocols to indicate the outcome of message transfers between endpoints. The vulnerability arises from naive range validation mechanisms that fail to properly sanitize or limit the size of range parameters within disposition frames, allowing malicious actors to craft specially crafted frames with excessively large or invalid range specifications.
The technical implementation of this vulnerability stems from inadequate input validation and resource management within the protocol parser component responsible for handling disposition frames. When the library processes these maliciously constructed frames, it employs inefficient algorithms that iterate through or process the specified ranges without proper bounds checking, leading to exponential CPU consumption patterns. This behavior aligns with CWE-704, which categorizes improper input validation as a fundamental weakness in software design and implementation practices. The lack of proper range size limitations enables attackers to trigger resource exhaustion conditions where the processing time grows disproportionately with the size of the malicious ranges, effectively creating a computational DoS scenario.
From an operational impact perspective, this vulnerability creates significant security concerns for systems relying on Apache Qpid Proton-Dotnet for messaging operations. The authenticated nature of the attack means that only users with valid credentials can exploit this flaw, but such access could come from compromised accounts or insider threats. The CPU exhaustion resulting from processing these frames can lead to complete service unavailability, system instability, and potential cascading failures in distributed messaging architectures where multiple components depend on reliable message processing capabilities. Organizations using this library in production environments face risks of service disruption that could affect business continuity and data flow integrity across their messaging infrastructure.
The recommended mitigation strategy involves upgrading to version 1.1.0 or later, which implements proper range validation mechanisms and resource limits for disposition frame processing. This upgrade addresses the root cause by introducing bounds checking, maximum range size enforcement, and efficient processing algorithms that prevent excessive CPU consumption. Additionally, system administrators should implement monitoring solutions to detect unusual CPU usage patterns that could indicate exploitation attempts, while also considering network-level controls such as rate limiting and access control policies to minimize the attack surface. The fix demonstrates adherence to security best practices outlined in the ATT&CK framework under the T1499 category of resource exhaustion techniques, where proper input validation and bounds checking are essential defensive measures against such vulnerabilities.
This vulnerability highlights the critical importance of robust input validation in protocol implementations and demonstrates how seemingly minor flaws in range handling can lead to significant security implications. The fix implemented in version 1.1.0 represents a standard defensive programming approach that includes proper error handling, resource management, and algorithmic efficiency improvements. Organizations should conduct thorough testing of upgraded components to ensure compatibility while also reviewing other protocol libraries for similar vulnerabilities that might expose their messaging infrastructure to analogous threats.