static struct hash_list *parse_merge(unsigned int *count)
{
	struct hash_list *list = NULL, **tail = &list, *n;
	const char *from;
	struct branch *s;

	*count = 0;
	while (skip_prefix(command_buf.buf, "merge ", &from)) {
		n = xmalloc(sizeof(*n));
		s = lookup_branch(from);
		if (s)
			hashcpy(n->sha1, s->sha1);
		else if (*from == ':') {
			uintmax_t idnum = parse_mark_ref_eol(from);
			struct object_entry *oe = find_mark(idnum);
			if (oe->type != OBJ_COMMIT)
				die("Mark :%" PRIuMAX " not a commit", idnum);
			hashcpy(n->sha1, oe->idx.sha1);
		} else if (!get_sha1(from, n->sha1)) {
			unsigned long size;
			char *buf = read_object_with_reference(n->sha1,
				commit_type, &size, n->sha1);
			if (!buf || size < 46)
				die("Not a valid commit: %s", from);
			free(buf);
		} else
			die("Invalid ref name or SHA1 expression: %s", from);

		n->next = NULL;
		*tail = n;
		tail = &n->next;

		(*count)++;
		read_next_command();
	}
	return list;
}

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.