[sk5t]

FWIW the first practical application of input tainting that comes to mind is Perl's circa 2001, although I wouldn't be surprised to hear Smalltalk went there before.

[eesmith]

FWIW, perl3 circa 1990 - https://en.wikipedia.org/wiki/Taint_checking#History .

[rurban]

Yeah, but with holes. Eg affecting Bugzilla. Only closed 2018 in cperl (hash keys). perl5 never cared to close its taint holes.