isdn_net_newslave(char *parm)
{
	char *p = strchr(parm, ',');
	isdn_net_dev *n;
	char newname[10];

	if (p) {
		/* Slave-Name MUST not be empty */
		if (!strlen(p + 1))
			return NULL;
		strcpy(newname, p + 1);
		*p = 0;
		/* Master must already exist */
		if (!(n = isdn_net_findif(parm)))
			return NULL;
		/* Master must be a real interface, not a slave */
		if (n->local->master)
			return NULL;
		/* Master must not be started yet */
		if (isdn_net_device_started(n)) 
			return NULL;
		return (isdn_net_new(newname, n->dev));
	}
	return NULL;
}

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