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