Cleveref fails to pick up the footnote number when using svmono 5.6 class

Question

Consider the following input:

\documentclass{svmono}%%% Version 5.6 from https://www.springer.com/gp/authors-editors/book-authors-editors/resources-guidelines/book-manuscript-guidelines/manuscript-preparation/5636
\pagestyle{empty}
\usepackage{cleveref}
\begin{document}
\begin{theorem}\label[theorem]{exmp:myExample}
  Text.\footnote{\label{ftnt:myFootnoteOne}First footnote.}
  Text.\footnote{\label[footnote]{ftnt:myFootnoteTwo}Second footnote.}
  Text.\footnote{\label{ftnt:myFootnoteThree}Third footnote.}
  Text.\footnote{\label[footnote]{ftnt:myFootnoteFour}Fourth footnote.}
\end{theorem}
References to footnotes 3 and 4 with \texttt{\textbackslash cref}: \cref{ftnt:myFootnoteThree}, \cref{ftnt:myFootnoteFour}.\\
References to footnotes 3 and 4 with \texttt{\textbackslash ref}: \ref{ftnt:myFootnoteThree}, \ref{ftnt:myFootnoteFour}.
\end{document}

Feeding this to either of pdflatex, xelatex, or lualatex results in a failure of \cref to determine and print the footnote numbers:

As we see, \cref prints the number of the enclosing environment (here, theorem) instead.

How to fix this? I informed the author of cleveref, but my attempts to reach out to Springer ended nowhere (an automatic answer emerged saying texhelp [at] springer [dot] com and texhelp [at] springer [dot] de are dead).

Answer 1

svmono overwrites at begin document the footnote definition of cleveref. So you should overwrite it again.

\documentclass{svmono}%%% Version 5.6 from https://www.springer.com/gp/authors-editors/book-authors-editors/resources-guidelines/book-manuscript-guidelines/manuscript-preparation/5636
\pagestyle{empty}
\usepackage{cleveref}
\makeatletter
\AtBeginDocument{%
\let\cref@old@makefntext\@makefntext%
\long\def\@makefntext{%
  \cref@constructprefix{footnote}{\cref@result}%
  \protected@edef\cref@currentlabel{%
    [footnote][\arabic{footnote}][\cref@result]%
    \p@footnote\@thefnmark}%
  \cref@old@makefntext}%
 } 
\makeatother 
\begin{document}
\begin{theorem}\label[theorem]{exmp:myExample}
  Text.\footnote{\label{ftnt:myFootnoteOne}First footnote.}
  Text.\footnote{\label[footnote]{ftnt:myFootnoteTwo}Second footnote.}
  Text.\footnote{\label{ftnt:myFootnoteThree}Third footnote.}
  Text.\footnote{\label[footnote]{ftnt:myFootnoteFour}Fourth footnote.}
\end{theorem}
References to footnotes 3 and 4 with \texttt{\textbackslash cref}: \cref{ftnt:myFootnoteThree}, \cref{ftnt:myFootnoteFour}.\\
References to footnotes 3 and 4 with \texttt{\textbackslash ref}: \ref{ftnt:myFootnoteThree}, \ref{ftnt:myFootnoteFour}.
\end{document}