diff --git a/libio/genops.c b/libio/genops.c
index 4f5c6136f3..bb1d9594eb 100644
--- a/libio/genops.c
+++ b/libio/genops.c
@@ -789,6 +789,12 @@ _IO_unbuffer_all (void)
 	legacy = 1;
 #endif
 
+      /* Free up the backup area if it was ever allocated.  */
+      if (_IO_have_backup (fp))
+	_IO_free_backup_area (fp);
+      if (fp->_mode > 0 && _IO_have_wbackup (fp))
+	_IO_free_wbackup_area (fp);
+
       if (! (fp->_flags & _IO_UNBUFFERED)
 	  /* Iff stream is un-orientated, it wasn't used. */
 	  && (legacy || fp->_mode != 0))
diff --git a/libio/libioP.h b/libio/libioP.h
index 1af287b19f..616253fcd0 100644
--- a/libio/libioP.h
+++ b/libio/libioP.h
@@ -577,8 +577,8 @@ extern void _IO_old_init (FILE *fp, int flags) __THROW;
        ((__fp)->_wide_data->_IO_write_base \
 	= (__fp)->_wide_data->_IO_write_ptr = __p, \
 	(__fp)->_wide_data->_IO_write_end = (__ep))
-#define _IO_have_backup(fp) ((fp)->_IO_save_base != NULL)
-#define _IO_have_wbackup(fp) ((fp)->_wide_data->_IO_save_base != NULL)
+#define _IO_have_backup(fp) ((fp)->_IO_backup_base != NULL)
+#define _IO_have_wbackup(fp) ((fp)->_wide_data->_IO_backup_base != NULL)
 #define _IO_in_backup(fp) ((fp)->_flags & _IO_IN_BACKUP)
 #define _IO_have_markers(fp) ((fp)->_markers != NULL)
 #define _IO_blen(fp) ((fp)->_IO_buf_end - (fp)->_IO_buf_base)
diff --git a/stdio-common/Makefile b/stdio-common/Makefile
index 159dc472e4..b9c38ce6b3 100644
--- a/stdio-common/Makefile
+++ b/stdio-common/Makefile
@@ -257,6 +257,7 @@ tests := \
   tst-swscanf \
   tst-tmpnam \
   tst-ungetc \
+  tst-ungetc-leak \
   tst-unlockedio \
   tst-vfprintf-mbs-prec \
   tst-vfprintf-user-type \
@@ -301,6 +302,7 @@ tests-special += \
   $(objpfx)tst-printfsz-islongdouble.out \
   $(objpfx)tst-setvbuf1-cmp.out \
   $(objpfx)tst-unbputc.out \
+  $(objpfx)tst-ungetc-leak-mem.out \
   $(objpfx)tst-vfprintf-width-prec-mem.out \
   # tests-special
 
@@ -315,6 +317,8 @@ generated += \
   tst-printf-fp-leak-mem.out \
   tst-printf-fp-leak.mtrace \
   tst-scanf-bz27650.mtrace \
+  tst-ungetc-leak-mem.out \
+  tst-ungetc-leak.mtrace \
   tst-vfprintf-width-prec-mem.out \
   tst-vfprintf-width-prec.mtrace \
   # generated
@@ -407,6 +411,9 @@ tst-printf-fp-leak-ENV = \
 tst-scanf-bz27650-ENV = \
   MALLOC_TRACE=$(objpfx)tst-scanf-bz27650.mtrace \
   LD_PRELOAD=$(common-objpfx)malloc/libc_malloc_debug.so
+tst-ungetc-leak-ENV = \
+  MALLOC_TRACE=$(objpfx)tst-ungetc-leak.mtrace \
+  LD_PRELOAD=$(common-objpfx)malloc/libc_malloc_debug.so
 
 $(objpfx)tst-unbputc.out: tst-unbputc.sh $(objpfx)tst-unbputc
 	$(SHELL) $< $(common-objpfx) '$(test-program-prefix)'; \
diff --git a/stdio-common/tst-ungetc-leak.c b/stdio-common/tst-ungetc-leak.c
new file mode 100644
index 0000000000..6c5152b43f
--- /dev/null
+++ b/stdio-common/tst-ungetc-leak.c
@@ -0,0 +1,32 @@
+/* Test for memory leak with ungetc when stream is unused.
+   Copyright The GNU Toolchain Authors.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <stdio.h>
+#include <mcheck.h>
+#include <support/check.h>
+#include <support/support.h>
+
+static int
+do_test (void)
+{
+  mtrace ();
+  TEST_COMPARE (ungetc('y', stdin), 'y');
+  return 0;
+}
+
+#include <support/test-driver.c>