diff -up bash-4.4/input.c.orig bash-4.4/input.c

--- bash-4.4/input.c.orig	2022-03-10 10:50:40.046490589 -0300

+++ bash-4.4/input.c	2022-03-10 10:51:48.659491601 -0300

@@ -530,7 +530,7 @@ bufstream_ungetc(c, bp)

      int c;

      BUFFERED_STREAM *bp;

 {

-  if (c == EOF || bp->b_inputp == 0)

+  if (c == EOF || bp == 0 || bp->b_inputp == 0)

     return (EOF);

   bp->b_buffer[--bp->b_inputp] = c;

@@ -561,6 +561,10 @@ buffered_getchar ()

 {

   CHECK_TERMSIG;

+  if (bash_input.location.buffered_fd < 0 ||

+      buffers[bash_input.location.buffered_fd] == 0)

+    return EOF;

+

 #if !defined (DJGPP)

   return (bufstream_getc (buffers[bash_input.location.buffered_fd]));

 #else