well I guess for a webserver gaining any privileges is already bad. of course privilege escalation is bad, especially on client machine's, but on servers? well

well I guess for a webserver gaining any privileges is already bad. of course privilege escalation is bad, especially on client machine's, but on servers? well if you are an attacker from the outside and already have a shell your security is done anyway. of course as said that won't apply to shared hosting (with shell) and client machines.