[Solved] Prevent User Agent malicious code with PHP [closed]

Question

Exactly the same way you should already prevent injection with every other value. That it’s specifically a user agent string is irrelevant. When writing it to an HTML page, pass it through htmlspecialchars: echo htmlspecialchars($user_agent);. When using it as part of a database query, use prepared statements, or whatever escaping function the the database API gives you.

Accepted Answer

Exactly the same way you should already prevent injection with every other value. That it’s specifically a user agent string is irrelevant. When writing it to an HTML page, pass it through htmlspecialchars: echo htmlspecialchars($user_agent);. When using it as part of a database query, use prepared statements, or whatever escaping function the the database API gives you.