diff --git a/iconv/Makefile b/iconv/Makefile
index d71319b39e..de6f55e087 100644
--- a/iconv/Makefile
+++ b/iconv/Makefile
@@ -43,7 +43,8 @@ CFLAGS-charmap.c += -DCHARMAP_PATH='"$(i18ndir)/charmaps"' \
 CFLAGS-linereader.c += -DNO_TRANSLITERATION
 CFLAGS-simple-hash.c += -I../locale
 
-tests	= tst-iconv1 tst-iconv2 tst-iconv3 tst-iconv4 tst-iconv5 tst-iconv6
+tests	= tst-iconv1 tst-iconv2 tst-iconv3 tst-iconv4 tst-iconv5 tst-iconv6 \
+	  tst-iconv8
 
 others		= iconv_prog iconvconfig
 install-others-programs	= $(inst_bindir)/iconv
diff --git a/iconv/gconv_simple.c b/iconv/gconv_simple.c
index 506c92caf2..8c84a43055 100644
--- a/iconv/gconv_simple.c
+++ b/iconv/gconv_simple.c
@@ -237,11 +237,9 @@ ucs4_internal_loop (struct __gconv_step *step,
   int flags = step_data->__flags;
   const unsigned char *inptr = *inptrp;
   unsigned char *outptr = *outptrp;
-  size_t n_convert = MIN (inend - inptr, outend - outptr) / 4;
   int result;
-  size_t cnt;
 
-  for (cnt = 0; cnt < n_convert; ++cnt, inptr += 4)
+  for (; inptr + 4 <= inend && outptr + 4 <= outend; inptr += 4)
     {
       uint32_t inval;
 
@@ -304,11 +302,9 @@ ucs4_internal_loop_unaligned (struct __gconv_step *step,
   int flags = step_data->__flags;
   const unsigned char *inptr = *inptrp;
   unsigned char *outptr = *outptrp;
-  size_t n_convert = MIN (inend - inptr, outend - outptr) / 4;
   int result;
-  size_t cnt;
 
-  for (cnt = 0; cnt < n_convert; ++cnt, inptr += 4)
+  for (; inptr + 4 <= inend && outptr + 4 <= outend; inptr += 4)
     {
       if (__glibc_unlikely (inptr[0] > 0x80))
 	{
@@ -607,11 +603,9 @@ ucs4le_internal_loop (struct __gconv_step *step,
   int flags = step_data->__flags;
   const unsigned char *inptr = *inptrp;
   unsigned char *outptr = *outptrp;
-  size_t n_convert = MIN (inend - inptr, outend - outptr) / 4;
   int result;
-  size_t cnt;
 
-  for (cnt = 0; cnt < n_convert; ++cnt, inptr += 4)
+  for (; inptr + 4 <= inend && outptr + 4 <= outend; inptr += 4)
     {
       uint32_t inval;
 
@@ -677,11 +671,9 @@ ucs4le_internal_loop_unaligned (struct __gconv_step *step,
   int flags = step_data->__flags;
   const unsigned char *inptr = *inptrp;
   unsigned char *outptr = *outptrp;
-  size_t n_convert = MIN (inend - inptr, outend - outptr) / 4;
   int result;
-  size_t cnt;
 
-  for (cnt = 0; cnt < n_convert; ++cnt, inptr += 4)
+  for (; inptr + 4 <= inend && outptr + 4 <= outend; inptr += 4)
     {
       if (__glibc_unlikely (inptr[3] > 0x80))
 	{
diff --git a/iconv/tst-iconv8.c b/iconv/tst-iconv8.c
new file mode 100644
index 0000000000..0b92b19f66
--- /dev/null
+++ b/iconv/tst-iconv8.c
@@ -0,0 +1,50 @@
+/* Test iconv behavior on UCS4 conversions with //IGNORE.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   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
+   <http://www.gnu.org/licenses/>.  */
+
+/* Derived from BZ #26923 */
+#include <errno.h>
+#include <iconv.h>
+#include <stdio.h>
+#include <support/check.h>
+
+static int
+do_test (void)
+{
+  iconv_t cd = iconv_open ("UTF-8//IGNORE", "ISO-10646/UCS4/");
+  TEST_VERIFY_EXIT (cd != (iconv_t) -1);
+
+  /*
+   * Convert sequence beginning with an irreversible character into buffer that
+   * is too small.
+   */
+  char input[12] = "\xe1\x80\xa1" "AAAAAAAAA";
+  char *inptr = input;
+  size_t insize = sizeof (input);
+  char output[6];
+  char *outptr = output;
+  size_t outsize = sizeof (output);
+
+  TEST_VERIFY (iconv (cd, &inptr, &insize, &outptr, &outsize) == -1);
+  TEST_VERIFY (errno == E2BIG);
+
+  TEST_VERIFY_EXIT (iconv_close (cd) != -1);
+
+  return 0;
+}
+
+#include <support/test-driver.c>