diff --git a/localedata/Makefile b/localedata/Makefile
index 94014370f5..4a23593cca 100644
--- a/localedata/Makefile
+++ b/localedata/Makefile
@@ -236,6 +236,7 @@ tests = \
   bug-iconv-trans \
   bug-setlocale1 \
   bug-usesetlocale \
+  tst-bz13988 \
   tst-c-utf8-consistency \
   tst-digits \
   tst-iconv-emojis-trans \
diff --git a/localedata/tst-bz13988.c b/localedata/tst-bz13988.c
new file mode 100644
index 0000000000..8d6f399bbc
--- /dev/null
+++ b/localedata/tst-bz13988.c
@@ -0,0 +1,53 @@
+/* Localized test for BZ #13988.
+   Copyright (C) 2025 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <locale.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <libc-diag.h>
+#include <support/check.h>
+
+#define PD "\xd9\xab"
+
+static int
+do_test (void)
+{
+  if (setlocale (LC_ALL, "fa_IR.UTF-8") == NULL)
+    FAIL_EXIT1 ("setlocale (LC_ALL, \"fa_IR.UTF-8\")");
+
+  char s[] = "+" PD "e";
+  FILE *f = fmemopen (s, strlen (s), "r");
+
+  /* Avoid: "warning: 'I' flag used with '%f' gnu_scanf format [-Wformat=]";
+     cf. GCC PR c/119514.  */
+  DIAG_PUSH_NEEDS_COMMENT;
+  DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wformat");
+
+  /* This should fail to parse a floating-point number, and leave 'e' in the
+     input.  */
+  double d;
+  TEST_VERIFY_EXIT (fscanf (f, "%Ilf", &d) == 0);
+  TEST_VERIFY_EXIT (fgetc (f) == 'e');
+
+  DIAG_POP_NEEDS_COMMENT;
+
+  return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/stdio-common/vfscanf-internal.c b/stdio-common/vfscanf-internal.c
index 87f23b5845..6817fc1542 100644
--- a/stdio-common/vfscanf-internal.c
+++ b/stdio-common/vfscanf-internal.c
@@ -2409,7 +2409,7 @@ digits_extended_fail:
 		      if (got_e && charbuf.current[-1] == exp_char
 			  && (c == L_('-') || c == L_('+')))
 			char_buffer_add (&charbuf, c);
-		      else if (char_buffer_size (&charbuf) > got_sign && !got_e
+		      else if (got_digit && !got_e
 			       && (CHAR_T) TOLOWER (c) == exp_char)
 			{
 			  char_buffer_add (&charbuf, exp_char);
@@ -2426,7 +2426,10 @@ digits_extended_fail:
 			      if (c == wcdigits[n])
 				{
 				  if (n < 10)
-				    char_buffer_add (&charbuf, L_('0') + n);
+				    {
+				      char_buffer_add (&charbuf, L_('0') + n);
+				      got_digit = 1;
+				    }
 				  else if (n == 11 && !got_dot)
 				    {
 				      char_buffer_add (&charbuf, decimal);
@@ -2461,7 +2464,10 @@ digits_extended_fail:
 				    width = avail;
 
 				  if (n < 10)
-				    char_buffer_add (&charbuf, L_('0') + n);
+				    {
+				      char_buffer_add (&charbuf, L_('0') + n);
+				      got_digit = 1;
+				    }
 				  else if (n == 11 && !got_dot)
 				    {
 				      /* Add all the characters.  */