Certainly the null byte can appear in utf-8; code points like \x2400, \x2500, . . . all have them
No, utf8 is specifically formulated to avoid null bytes in any codepoints apart from zero, eg 
$ perl586 -MDevel::Peek -e'Dump "\x{2400}"'
SV = PV(0x8181f00) at 0x816e234
  REFCNT = 1
  FLAGS = (POK,READONLY,pPOK,UTF8)
  PV = 0x817c268 "\342\220\200"\0 [UTF8 "\x{2400}"]
  CUR = 3
  LEN = 4

[download]
That codepoint is represented by three bytes, none of which is zero.

Dave.

In reply to Re^2: Extra CGI.pm safety by stripping \x00 bytes? by dave_the_m
in thread Extra CGI.pm safety by stripping \x00 bytes? by rlucas

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