session_open(Authctxt *authctxt, int chanid)
{
	Session *s = session_new();
	debug("session_open: channel %d", chanid);
	if (s == NULL) {
		error("no more sessions");
		return 0;
	}
	s->authctxt = authctxt;
	s->pw = authctxt->pw;
	if (s->pw == NULL || !authctxt->valid)
		fatal("no user for session %d", s->self);
	debug("session_open: session %d: link with channel %d", s->self, chanid);
	s->chanid = chanid;
	return 1;
}

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