CVE-2024-50595 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 series of network requests can lead to denial of service. An attacker can send a sequence of malicious packets to trigger this vulnerability.This vulnerability affects the NetX Duo Component HTTP Server implementation which can be found in x-cube-azrtos-f7\Middlewares\ST\netxduo\addons\http\nxd_http_server.c
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Analysis
by VulDB Data Team • 09/05/2025
The integer underflow vulnerability identified in CVE-2024-50595 represents a critical flaw within the STMicroelectronics X-CUBE-AZRTOS-WL 2.0.0 software stack, specifically impacting the NetX Duo Component HTTP Server implementation. This vulnerability manifests within the PUT request handling functionality of the embedded HTTP server component, which is a core element of the middleware architecture designed for Azure RTOS-based applications. The affected code path is located in the x-cube-azrtos-f7\Middlewares\ST\etxduo\addons\http\xd_http_server.c file, making it a fundamental component in the software's network communication capabilities. The vulnerability stems from improper input validation and arithmetic handling when processing HTTP PUT requests, creating a scenario where integer underflow conditions can be exploited by malicious actors.
The technical exploitation of this vulnerability occurs when an attacker crafts and sends a sequence of specially formatted network packets that manipulate the integer values used in the HTTP server's request processing logic. The integer underflow condition arises when a decrement operation on an unsigned integer results in a value that wraps around to a large positive number instead of the expected negative value, creating unpredictable behavior in the application's memory management and control flow. This specific implementation flaw falls under CWE-191, which categorizes integer underflows as a common class of vulnerabilities in software systems. The vulnerability's impact is particularly concerning because it affects the core HTTP server functionality that handles file uploads and resource modifications, making it a potential vector for service disruption attacks.
From an operational perspective, this vulnerability creates a significant risk of denial of service conditions that can severely impact the availability of network services provided by devices running the affected software stack. The malicious packet sequence can cause the HTTP server to enter an unstable state where it either crashes completely or becomes unresponsive to legitimate requests, effectively rendering the device's network capabilities unusable. The attack surface is particularly broad as the vulnerability affects embedded systems that rely on Azure RTOS for real-time operations, potentially impacting industrial control systems, IoT devices, and networked embedded applications where continuous availability is critical. Network administrators and security professionals must understand that this vulnerability can be exploited remotely without requiring authentication, making it particularly dangerous in environments where such devices are exposed to untrusted network traffic.
The mitigation strategies for this vulnerability should focus on immediate software updates and patches provided by STMicroelectronics, as the company is responsible for addressing the root cause within the NetX Duo Component HTTP Server implementation. Organizations should implement network segmentation and access controls to limit exposure to untrusted networks, while also monitoring for suspicious network activity that might indicate exploitation attempts. The vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and represents a clear example of how embedded system vulnerabilities can create cascading effects in networked environments. Additionally, implementing network intrusion detection systems and conducting regular security assessments of embedded firmware components can help identify similar vulnerabilities before they can be exploited in production environments. The fix should involve proper bounds checking and integer validation in the HTTP server's PUT request processing logic to prevent underflow conditions from occurring during normal operation.