From https://ftp.gnu.org/gnu/bash/bash-5.0-patches/bash50-011

Signed-off-by: Pascal de Bruijn <p.debruijn@unilogic.nl>

			     BASH PATCH REPORT
			     =================

Bash-Release:	5.0
Patch-ID:	bash50-011

Bug-Reported-by:	Matt Whitlock
Bug-Reference-ID:	
Bug-Reference-URL:	https://savannah.gnu.org/support/?109671

Bug-Description:

The conditional command did not perform appropriate quoted null character
removal on its arguments, causing syntax errors and attempts to stat
invalid pathnames.

Patch (apply with `patch -p0'):

*** ../bash-5.0-patched/subst.c	2018-12-22 17:43:37.000000000 -0500
--- b/subst.c	2019-04-14 13:25:41.000000000 -0400
***************
*** 3626,3630 ****
     SPECIAL is 2, this is an rhs argument for the =~ operator, and should
     be quoted appropriately for regcomp/regexec.  The caller is responsible
!    for removing the backslashes if the unquoted word is needed later. */   
  char *
  cond_expand_word (w, special)
--- 3642,3648 ----
     SPECIAL is 2, this is an rhs argument for the =~ operator, and should
     be quoted appropriately for regcomp/regexec.  The caller is responsible
!    for removing the backslashes if the unquoted word is needed later. In
!    any case, since we don't perform word splitting, we need to do quoted
!    null character removal. */
  char *
  cond_expand_word (w, special)
***************
*** 3647,3650 ****
--- 3665,3670 ----
        if (special == 0)			/* LHS */
  	{
+ 	  if (l->word)
+ 	    word_list_remove_quoted_nulls (l);
  	  dequote_list (l);
  	  r = string_list (l);
*** ../bash-5.0/patchlevel.h	2016-06-22 14:51:03.000000000 -0400
--- b/patchlevel.h	2016-10-01 11:01:28.000000000 -0400
***************
*** 26,30 ****
     looks for to find the patch level (for the sccs version string). */
  
! #define PATCHLEVEL 10
  
  #endif /* _PATCHLEVEL_H_ */
--- 26,30 ----
     looks for to find the patch level (for the sccs version string). */
  
! #define PATCHLEVEL 11
  
  #endif /* _PATCHLEVEL_H_ */