CVE-2024-50596 in X-CUBE-AZRT-H7RS
Summary
by MITRE • 04/02/2025
An integer underflow vulnerability exists in the HTTP server PUT request functionality of STMicroelectronics X-CUBE-AZRTOS-WL 2.0.0. A specially crafted network packet can lead to denial of service. An attacker can send a malicious packet to trigger this vulnerability.This vulnerability affects the NetX Duo Web Component HTTP Server implementation which can be found in x-cube-azrtos-f7\Middlewares\ST\netxduo\addons\web\nx_web_http_server.c
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Analysis
by VulDB Data Team • 09/05/2025
The vulnerability identified as CVE-2024-50596 represents a critical integer underflow condition within the HTTP server implementation of STMicroelectronics X-CUBE-AZRTOS-WL 2.0.0 software stack. This flaw specifically manifests within the PUT request handling functionality of the NetX Duo Web Component HTTP Server, which is integrated into the x-cube-azrtos-f7 middleware suite. The vulnerability resides in the x_web_http_server.c source file located within the middleware components directory structure, making it a core component of the embedded web server functionality that powers various IoT and embedded applications utilizing STMicroelectronics hardware platforms. The integer underflow occurs when processing certain HTTP PUT requests, where malformed or specially crafted network packets can cause arithmetic operations to produce unexpectedly small or negative integer values, fundamentally disrupting normal program execution flow.
The technical exploitation of this vulnerability leverages the inherent weakness in input validation and arithmetic handling within the HTTP server's request processing pipeline. When a malicious packet is transmitted to the affected system, the server's PUT request handler fails to properly validate the size parameters or content length indicators within the HTTP headers. This validation failure allows an attacker to craft a packet where the integer calculations used to determine buffer sizes or memory allocation limits result in underflow conditions, typically producing negative values or values that exceed the expected range. The underlying implementation appears to lack proper boundary checks and overflow protection mechanisms, creating a scenario where legitimate network traffic processing can be disrupted by malicious inputs. This flaw falls under the CWE-191 Integer Underflow (Wrap) category, which specifically addresses situations where integer arithmetic produces values that are outside the range of the data type, leading to unpredictable behavior and potential system instability.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it represents a fundamental security weakness that can compromise the reliability and availability of embedded systems utilizing the affected software stack. When triggered, the integer underflow causes the HTTP server component to enter an undefined state where it may crash, restart unexpectedly, or become unresponsive to legitimate requests. This disruption affects the overall system functionality, particularly in IoT deployments where continuous availability is critical for device operation and communication with cloud services or other networked components. The vulnerability affects embedded applications that rely on the NetX Duo Web Component for HTTP services, potentially impacting industrial control systems, smart home devices, automotive infotainment systems, and various other embedded platforms where STMicroelectronics processors and RTOS implementations are deployed. The attack surface is particularly concerning as it can be exploited remotely through network-based attacks without requiring physical access to the target device, making it a significant risk for connected embedded systems in operational environments.
Mitigation strategies for CVE-2024-50596 should prioritize immediate software updates from STMicroelectronics, as the vendor is likely to provide patches addressing the integer underflow condition in the HTTP server implementation. Organizations should implement network-level controls such as firewall rules and access control lists to restrict access to the affected HTTP server ports and services where possible. The implementation of proper input validation and bounds checking within the application layer can provide additional defense-in-depth measures, ensuring that all HTTP request parameters are properly validated before processing. Security monitoring should be enhanced to detect anomalous network traffic patterns that might indicate exploitation attempts, particularly around HTTP PUT request handling. The vulnerability aligns with ATT&CK technique T1210 Exploitation of Remote Services, as it represents a network-based attack vector targeting a remote service component. Additionally, this issue demonstrates the importance of secure coding practices and the need for comprehensive testing of arithmetic operations in embedded systems, particularly in components that handle network input. Organizations should also consider implementing intrusion detection systems specifically configured to identify malformed HTTP requests that could trigger integer underflow conditions, and conduct regular security assessments of embedded systems to identify similar vulnerabilities in other components of the software stack.