PatchSiren cyber security CVE debrief

CVE-2026-54413 driftregion CVE debrief

CVE-2026-54413 is an integer underflow and downstream out-of-bounds read vulnerability in the Handle_0x27_SecurityAccess() function in iso14229.c. This vulnerability allows a remote unauthenticated attacker to crash a UDS server and potentially read memory past the receive buffer by sending a single-byte 0x27 SecurityAccess request that follows any earlier well-formed 0x27 message. The handler reads the SecurityAccess subFunction from recv_buf[1] without first checking that recv_len is at least 2, then computes the key-data length as the unsigned subtraction (uint16_t)(recv_len - UDS_0X27_REQ_BASE_LEN); when recv_len equals 1 the result underflows to 65535 and is passed as args.len to the application's SecAccessValidateKey or SecAccessRequestSeed callback, which typically iterates or copies that many bytes from the 4-KB receive buffer.