The uds-c library contains a stack buffer overflow in the send_diagnostic_request function. The payload buffer is only six bytes long, yet the implementation copies up to seven bytes of payload data without verifying the length, causing the buffer to be overwritten and memory corruption. As a result, this flaw could allow an attacker to corrupt stack data and potentially execute arbitrary code or crash the application. The flaw is classified as high severity with a CVSS score of 8.8, indicating a substantial impact if successfully exploited.

The affected component is the uds‑c diagnostic library used in automotive communication stacks. The vulnerability exists in the commit e506334e270d77b20c0bc259ac6c7d8c9b702b7a (dated 2016‑10‑05). Users relying on earlier releases of the library are at risk; any build that includes this commit without the later fix is affected.

The CVSS score of 8.8 signals a severe risk, and while the EPSS score is not available, the lack of a bounds check and the high severity suggest that the flaw could be exploited remotely via crafted diagnostic requests sent over a network or other communication interface. Based on the description, it is inferred that an attacker would need to send a specially crafted diagnostic packet that exceeds the payload length limit to trigger the overflow. The vulnerability is not yet listed in CISA KEV, but its high severity warrants immediate attention and mitigation.