The vulnerability in CVE-2026-42485 involves a stack buffer overflow in the uds-c library's send_diagnostic_request function. The function allocates a fixed 6-byte buffer but copies up to 7 bytes based on the payload_length field without validating that the payload fits. This unchecked memcpy operation leads to a 1-4 byte overflow on the stack. Because the target environment is 32-bit ARM automotive ECUs without stack canaries, the overflow can overwrite the return address, potentially enabling remote code execution.

Successful exploitation of this vulnerability can lead to arbitrary code execution on affected 32-bit ARM automotive ECUs that do not implement stack canaries. This could compromise the integrity and security of automotive systems relying on the uds-c library for diagnostic communication. No known exploits are reported in the wild at this time.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, users should monitor vendor communications for updates. No specific mitigations or workarounds are provided in the available data.