Comment # 7 on bug 1213353 from Dr. Werner Fink

The crash is caused by abort called via malloc_printerr() here in 
malloc_consolidate() of glibc-2.37/malloc/malloc.c

      do {
        {
          if (__glibc_unlikely (misaligned_chunk (p)))
            malloc_printerr ("malloc_consolidate(): "
                             "unaligned fastbin chunk detected");

          unsigned int idx = fastbin_index (chunksize (p));
          if ((&fastbin (av, idx)) != fb)
            malloc_printerr ("malloc_consolidate(): invalid chunk size");
        }

and as

 static void
 malloc_printerr (const char *str)
 {
 #if IS_IN (libc)
   __libc_message ("%s\n", str);
 #else
   __libc_fatal (str);
 #endif
   __builtin_unreachable ();
 }

both __libc_message() and __libc_fatal() (via __libc_message()) call abort()
... AFAICS glibc-2.37/sysdeps/posix/libc_fatal.c

...note sure if this is a bash/libreadline problem here.