CVE-2025-6093 is a stack-based buffer overflow vulnerability identified in the uYanki board-stm32f103rc-berial product, specifically affecting the function heartrate1_i2c_hal_write located in the source file 7.Example/hal/i2c/max30100/Manual/demo2/2/heartrate1_hal.c. The vulnerability arises due to improper handling of the argument 'num', which can be manipulated to cause a buffer overflow on the stack. This type of vulnerability can lead to memory corruption, potentially allowing an attacker to execute arbitrary code, crash the system, or cause denial of service. The product uses continuous delivery with rolling releases, which means specific version details of affected or patched releases are not available. The CVSS v4.0 score is 5.1 (medium severity), with the vector indicating that the attack requires adjacent network access (AV:A), low attack complexity (AC:L), no attack vector (AT:N), low privileges (PR:L), no user interaction (UI:N), and low impact on confidentiality, integrity, and availability (VC:L, VI:L, VA:L). No known exploits are currently in the wild. The affected product is based on the STM32F103RC microcontroller, commonly used in embedded systems and IoT devices, particularly in sensor and control applications such as heart rate monitoring (as indicated by the max30100 sensor reference). The vulnerability's exploitation could allow an attacker on the same local network segment to cause memory corruption by sending crafted data to the device's I2C interface, potentially leading to device malfunction or code execution within the constraints of the device's environment.

For European organizations, the impact of this vulnerability depends largely on the deployment of the uYanki board-stm32f103rc-berial in their operational technology (OT) or embedded systems environments. Given that the affected product is an embedded board likely used in sensor or control systems (e.g., medical devices, industrial automation, or IoT deployments), exploitation could lead to disruption of critical monitoring or control functions. This may result in inaccurate sensor readings, system crashes, or unauthorized control, impacting operational continuity and safety. Confidentiality impact is limited due to the local network attack vector and low impact rating, but integrity and availability could be moderately affected. Organizations relying on these devices for health monitoring or industrial processes may face operational risks, including downtime or safety hazards. The medium severity rating suggests that while the vulnerability is not trivial, exploitation requires proximity and some level of access, limiting large-scale remote attacks but posing a risk in environments where local network access is possible. The lack of known exploits reduces immediate risk but does not eliminate it, especially as attackers may develop exploits over time.

1. Network Segmentation: Isolate devices using the uYanki board-stm32f103rc-berial on separate VLANs or network segments to restrict access to trusted devices only, minimizing the risk of an attacker gaining adjacent network access. 2. Access Control: Implement strict access controls and monitoring on local networks where these devices operate, including MAC filtering and network anomaly detection to identify suspicious activity targeting I2C communication interfaces. 3. Firmware Updates: Engage with the vendor to obtain patched firmware or rolling release updates addressing this vulnerability. If unavailable, consider applying custom patches or mitigations at the firmware level to validate and sanitize input parameters such as 'num' in the heartrate1_i2c_hal_write function. 4. Device Hardening: Disable or restrict unnecessary interfaces and services on the device to reduce the attack surface. 5. Monitoring and Incident Response: Deploy monitoring solutions to detect abnormal device behavior or crashes indicative of exploitation attempts, and prepare incident response plans specific to embedded device compromise. 6. Physical Security: Ensure physical access to devices is controlled to prevent direct manipulation or connection to the I2C bus. 7. Vendor Communication: Maintain active communication with uYanki for timely updates, patches, and security advisories related to this vulnerability.