If a user is able to access the privileges of higher roles than the role he has actually been assigned, he does so by intercepting and changing the values of the parameters that are sent by a browser to the server. In the case select the weakness that fits best in this scenario.

The scenario describes parameter tampering - a user modifying browser-sent values to gain higher privileges. This indicates the server is not validating whether the user should actually have those privileges. Option B (client-side validation) is insufficient because client validation can be bypassed. Option C (lack of server-side validation) is correct - the server must verify user permissions rather than trusting client-sent parameters. Options A and D are unrelated to the core issue.