evutil_hex_char_to_int_(char c)
{
	switch(c)
	{
		case '0': return 0;
		case '1': return 1;
		case '2': return 2;
		case '3': return 3;
		case '4': return 4;
		case '5': return 5;
		case '6': return 6;
		case '7': return 7;
		case '8': return 8;
		case '9': return 9;
		case 'A': case 'a': return 10;
		case 'B': case 'b': return 11;
		case 'C': case 'c': return 12;
		case 'D': case 'd': return 13;
		case 'E': case 'e': return 14;
		case 'F': case 'f': return 15;
	}
	return -1;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.