static int parse_data(struct strbuf *sb, uintmax_t limit, uintmax_t *len_res)
{
	const char *data;
	strbuf_reset(sb);

	if (!skip_prefix(command_buf.buf, "data ", &data))
		die("Expected 'data n' command, found: %s", command_buf.buf);

	if (skip_prefix(data, "<<", &data)) {
		char *term = xstrdup(data);
		size_t term_len = command_buf.len - (data - command_buf.buf);

		strbuf_detach(&command_buf, NULL);
		for (;;) {
			if (strbuf_getline(&command_buf, stdin, '\n') == EOF)
				die("EOF in data (terminator '%s' not found)", term);
			if (term_len == command_buf.len
				&& !strcmp(term, command_buf.buf))
				break;
			strbuf_addbuf(sb, &command_buf);
			strbuf_addch(sb, '\n');
		}
		free(term);
	}
	else {
		uintmax_t len = strtoumax(data, NULL, 10);
		size_t n = 0, length = (size_t)len;

		if (limit && limit < len) {
			*len_res = len;
			return 0;
		}
		if (length < len)
			die("data is too large to use in this context");

		while (n < length) {
			size_t s = strbuf_fread(sb, length - n, stdin);
			if (!s && feof(stdin))
				die("EOF in data (%lu bytes remaining)",
					(unsigned long)(length - n));
			n += s;
		}
	}

	skip_optional_lf();
	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.