CVE-2026-110944 in Qt
Summary
by MITRE • 11/04/2026
Resource exhaustion vulnerability in the HTTP request handling of the QHttpServer component of Qt HTTP Server.
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Analysis
by VulDB Data Team • 11/04/2026
The identified vulnerability resides within the HTTP request processing logic of the QHttpServer module, a core component of the Qt framework used for building networked applications and web servers. This specific flaw is classified as a resource exhaustion vulnerability, which fundamentally stems from an inability to properly manage or limit system resources during high-volume or malformed input scenarios. In typical operation, the server allocates memory buffers, file descriptors, or thread contexts to handle incoming HTTP connections. However, due to insufficient validation of request parameters or lack of rate limiting mechanisms, an attacker can exploit this weakness by sending a rapid succession of requests that trigger excessive resource allocation without corresponding release or cleanup procedures. This behavior leads to a gradual depletion of available system resources such as memory (RAM) and processing capacity, ultimately causing the server process to become unresponsive or crash entirely.
From a technical perspective, this issue aligns with CWE-400, which describes conditions where an application does not properly control the allocation and maintenance of a limited resource, thereby enabling an attacker to consume all available resources. The vulnerability is particularly dangerous because it can be triggered remotely without requiring authentication in many default configurations. An adversary could utilize automated tools to flood the target server with HTTP requests that are designed to maximize memory usage per connection or delay response times indefinitely. This type of attack vector is consistent with techniques documented under MITRE ATT&CK ID T1499, specifically Endpoint Denial of Service via resource exhaustion. The lack of built-in safeguards against slowloris-style attacks or large header injection means that even a single client can degrade the performance of the entire service by holding connections open and consuming server-side buffers indefinitely.
The operational impact of this vulnerability is severe for any production environment relying on Qt HTTP Server for public-facing services. A successful exploitation results in a denial-of-service condition where legitimate users are unable to access the application due to resource saturation. In cloud-native or containerized environments, this can trigger automatic restarts of pods or virtual machines, leading to cascading failures across dependent microservices and increased operational costs due to auto-scaling triggers responding falsely to perceived traffic spikes. Furthermore, if the server is part of a larger infrastructure, the instability caused by frequent crashes can disrupt data integrity checks or session management processes that rely on continuous availability.
Mitigation strategies must focus on implementing robust resource limits and input validation at both the application layer and network perimeter. Developers should configure maximum header sizes, connection timeouts, and request rate limiting within the QHttpServer configuration to prevent any single client from monopolizing server resources. Additionally, deploying a reverse proxy such as Nginx or Apache in front of the Qt HTTP Server can provide an additional layer of defense by absorbing initial traffic spikes and enforcing stricter timeout policies before requests reach the vulnerable component. Regular security audits focusing on resource management patterns and stress testing under high-load conditions are essential to identify and remediate similar weaknesses before they can be exploited in a live environment.