CallBackery versions before 0.62.0 for Perl accept unintended values in form fields checked by createRxValidator

CallBackery versions before 0.62.0 for Perl accept unintended values in form fields checked by createRxValidator.

createRxValidator() is documented to anchor the supplied pattern at both ends, but builds /^${rx}$/ without grouping the pattern. An alternation such as yes|no then accepts any value starting with yes or ending with no, and $ also accepts a value with one trailing newline.

An authenticated user can submit values the pattern was meant to reject, which an application may then write into generated configuration files.