static struct object_entry *parse_treeish_dataref(const char **p)
{
	unsigned char sha1[20];
	struct object_entry *e;

	if (**p == ':') {	/* <mark> */
		e = find_mark(parse_mark_ref_space(p));
		if (!e)
			die("Unknown mark: %s", command_buf.buf);
		hashcpy(sha1, e->idx.sha1);
	} else {	/* <sha1> */
		if (get_sha1_hex(*p, sha1))
			die("Invalid dataref: %s", command_buf.buf);
		e = find_object(sha1);
		*p += 40;
		if (*(*p)++ != ' ')
			die("Missing space after tree-ish: %s", command_buf.buf);
	}

	while (!e || e->type != OBJ_TREE)
		e = dereference(e, sha1);
	return e;
}

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.