CVE-2026-116337 in Qt
Summary
by MITRE • 11/09/2026
Uncontrolled resource consumption vulnerability in the Qt Framework HTTP response handling functionality of the Qt Network module.
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Analysis
by VulDB Data Team • 11/09/2026
The identified vulnerability resides within the Qt Network module's HTTP response handling subsystem, specifically affecting how the framework processes incoming data streams from remote servers. This flaw is classified as an uncontrolled resource consumption issue, which aligns with Common Weakness Enumeration identifier CWE-400. In this context, the application fails to adequately validate or limit the size of resources allocated during the parsing and processing of HTTP responses. When a client initiates a request to a potentially malicious server, that server can craft an HTTP response designed to trigger excessive memory allocation or CPU usage within the Qt framework's internal buffers. The vulnerability exploits the assumption that incoming data will be well-formed and bounded by reasonable limits, allowing attackers to bypass these implicit expectations through carefully constructed payloads.
From a technical perspective, the flaw likely stems from insufficient checks on content-length headers or chunked transfer encoding mechanisms before memory is committed for storage. If an attacker sends a response with a significantly larger payload than expected, or one that triggers recursive parsing logic without depth limits, the application may consume disproportionate amounts of system resources. This can lead to rapid exhaustion of available RAM, causing the process to crash due to out-of-memory conditions, or it can induce severe performance degradation by monopolizing CPU cycles during intensive decompression or parsing operations. Such behavior is characteristic of Denial of Service attacks where the goal is not necessarily code execution but rather service disruption through resource starvation.
The operational impact of this vulnerability is primarily centered on availability and stability. For applications relying heavily on Qt Network for web connectivity, such as desktop clients, embedded systems, or IoT devices with limited processing power, a successful exploit can result in application crashes, system freezes, or unresponsiveness. In multi-threaded environments where multiple network requests are handled concurrently, the impact may be amplified, potentially affecting other parts of the application that share the same memory space. This poses a significant risk to services requiring high uptime and reliability, as attackers do not need sophisticated exploitation techniques beyond sending malformed HTTP responses; they simply need to trigger the resource exhaustion condition repeatedly or sustain it over time.
Mitigation strategies should focus on implementing strict input validation and resource limits within the application layer where possible, although reliance solely on framework patches is often necessary for deep-seated issues like this. Developers should ensure that their applications are updated with the latest versions of the Qt Framework which include fixes for CWE-400 related flaws in network modules. Additionally, deploying web application firewalls or reverse proxies capable of inspecting and limiting response sizes can provide an external layer of defense by truncating excessively large responses before they reach the vulnerable client software. Monitoring system resource usage during network operations can also aid in detecting potential abuse attempts early, allowing for automated termination of suspicious connections to preserve overall system stability.