session_by_tty(char *tty)
{
	int i;
	for (i = 0; i < sessions_nalloc; i++) {
		Session *s = &sessions[i];
		if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) {
			debug("session_by_tty: session %d tty %s", i, tty);
			return s;
		}
	}
	debug("session_by_tty: unknown tty %.100s", tty);
	session_dump();
	return NULL;
}

This category addresses vulnerabilities caused by flawed access control mechanisms, where incorrect permission settings allow unauthorized users to access restricted resources.