title: Is there any way to put malicious code into a regular expression?
body: <p>I want to add regular expression search capability to my public web page. Other than <a href="http://en.wikipedia.org/wiki/HTML" rel="noreferrer">HTML</a> encoding the output, do I need to do anything to guard against malicious user input?</p>
  
  <p>Google searches are swamped by people solving the converse problem-- using regular expressions to detect malicious input--which I'm not interested in. In my scenario, the user input <em>is</em> a regular expression.</p>
  
  <p>I'll be using the <em>Regex</em> library in .NET (C#).</p>