Suppose I reconfigure my HTTP server to add the following HTTP header into every reply:

X-Hello: Hello!

or some other presumably funny text.

Can this have any negative effect on the server security?

  • not a security issue, but extra headers do consume (some) extra bandwidth.
    – Jacco
    Dec 13, 2012 at 12:07

3 Answers 3


No. It has absolutely zero effect.


It depends what the header is.

Assuming it is a made-up, X--prefixed, custom header, with a static value, then @Polynomial's answer is correct - it has absolutely no effect.

If you build the header value based on something else - e.g. the user's password - then that obviously would be A Bad Thing™.


As long as you don't disclose info potentially valuable to a would be attacker you are fine. X-our-awesome-stack: Software vX.YZ, Anothersoft vX.YZ, we dont believe in input santiziation! could disclose info that you might not want to advertise. X-Hello: What's up type of headers are absolutely harmless.

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