On macOS 14.5 running Zsh 5.9, the following command crashes Zsh:

% zsh -c "printf -v result \" %5'd\""

zsh:printf:1: %5': invalid directive

zsh(41890,0x7ff8450ddfc0) malloc: *** error for object 0x600002c811e0:
pointer being realloc'd was not allocated

zsh(41890,0x7ff8450ddfc0) malloc: *** set a breakpoint in
malloc_error_break to debug

zsh: abort      zsh -c "printf -v result \" %5'd\""

Surprisingly, dropping the -v option, removing the space before the %, or
adding an echo command after the printf command avoid the crash:

% zsh -c "printf \" %5'd\""

zsh:printf:1: %5': invalid directive

 *%*

% zsh -c "printf -v result \"%5'd\""

zsh:printf:1: %5': invalid directive

% zsh -c "printf -v result \" %5'd\"; echo foo"

zsh:printf:1: %5': invalid directive

foo

Philippe