A follow-up to Enforcing a question minimum character length?, and an extension of Spaces getting past minimum character limit.

This post shows that it is possible to circumvent minimum character requirements using null bytes. Can we exclude such non-printing characters as ASCII NULL and other control characters from counting toward minimum character requirements?

Edit: Users have demonstrated that HTML comments, unmatched or invalid HTML tags, and other content that is not displayed after Markdown parsing can be used to bypass such requirements as well. Can we cover this case as well, except for links?

  • 1
    There are other ways to get around it than using those characters. What does it solve?
    – animuson StaffMod
    Jun 21, 2012 at 0:22
  • 1
    IMO this is just trying way too hard for what is, at worst, an amusing oddity rather than a dangerous exploit.
    – Ben Brocka
    Jun 21, 2012 at 1:15
  • 1
    Yeah, why do you want to prevent this... it's so much fun! Jun 21, 2012 at 1:17
  • Soft hyphen
    – Jason OOO
    Oct 10, 2013 at 6:17
  • You should also not count the @username part towards the minimum characters in a case in which it will be stripped from the output. Like this case: If I type @DragonLordtheFiery at the beginning of this comment, it should not count toward the character minimum as it will be stripped from the output.
    – user215114
    Oct 10, 2013 at 15:47
  • ­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­ May 28, 2017 at 14:33
  • I think that content that isn't displayed shouldn't count towards the maximum character limit for comments. It's really annoying when I need to link to a page with a long URL in a comment and don't have enough characters for anything else. For example, if I add one more character to the following comment, it will be too long. Nov 9, 2017 at 19:57
  • This is almost too long. Nov 9, 2017 at 19:58

2 Answers 2


I'm not sure this is going to actually help anything. As users who can't reach the minimum character count have demonstrated, they'd rather find odd ways of avoiding the minimum limit that require more effort than just typing some extra text that supplements their answer.

Which of these would you rather see?





Yes. ____________

If people really don't want to think up a simple 15 characters, there's nothing that's going to stop them. Most users who don't know about the null byte characters and the HTML comments just fill the space with random, meaningless characters such as sjfgshjfs to bypass the limit, or use other styles (headers, bold, italics) to make the text stand out when it doesn't need to stand out.

Personally, I'd much rather see the first one. It may be a character bypass, but at least it doesn't look stupid in general when you look at it. Ultimately answers which use these are probably not real answers anyways* and will end up deleted or get fixed by someone else.

* Unless you're on Meta.

  • 1
    You're right. I concede. :P
    – bwDraco
    Jun 21, 2012 at 1:41


  • 4
    To this day, it's still possible to use null bytes to bypass minimum character requirements.
    – bwDraco
    Jun 21, 2012 at 1:14
  • 1
    – bfavaretto
    Aug 31, 2012 at 5:41
  • Well, null bytes have no place in text fields, so why should they be allowed? That's the point I'm trying to make. In fact, under certain circumstances, this can be a security vulnerability. This is another example of failing to sanitize input.
    – bwDraco
    Aug 31, 2012 at 12:36
  • I haven't used null bytes, but the zero-width space character U+200B
    – bfavaretto
    Aug 31, 2012 at 15:42
  • Okay, so they aren't null bytes. It turns out my hex editor didn't properly support Unicode...
    – bwDraco
    Aug 31, 2012 at 22:35
  • Null bytes may work, but this is nothing new. Zero-width spaces, soft hyphens, zero-width non-joiners... there's no point in banning them all (that's what happened to the ZWNJ and it really didn't work).
    – Ry-
    Aug 31, 2012 at 22:40

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