diff --git a/ext/mbstring/libmbfl/filters/mbfilter_iso8859_7.c b/ext/mbstring/libmbfl/filters/mbfilter_iso8859_7.c
index 64763dbcfed..63ae85e84e3 100644
--- a/ext/mbstring/libmbfl/filters/mbfilter_iso8859_7.c
+++ b/ext/mbstring/libmbfl/filters/mbfilter_iso8859_7.c
@@ -31,6 +31,8 @@
 #include "mbfilter_iso8859_7.h"
 #include "unicode_table_iso8859_7.h"
 
+static int mbfl_filt_ident_iso8859_7(int c, mbfl_identify_filter *filter);
+
 static const char *mbfl_encoding_8859_7_aliases[] = {"ISO8859-7", "greek", NULL};
 
 const mbfl_encoding mbfl_encoding_8859_7 = {
@@ -47,7 +49,7 @@ const mbfl_encoding mbfl_encoding_8859_7 = {
 const struct mbfl_identify_vtbl vtbl_identify_8859_7 = {
 	mbfl_no_encoding_8859_7,
 	mbfl_filt_ident_common_ctor,
-	mbfl_filt_ident_true
+	mbfl_filt_ident_iso8859_7
 };
 
 const struct mbfl_convert_vtbl vtbl_8859_7_wchar = {
@@ -132,3 +134,11 @@ int mbfl_filt_conv_wchar_8859_7(int c, mbfl_convert_filter *filter)
 
 	return c;
 }
+
+static int mbfl_filt_ident_iso8859_7(int c, mbfl_identify_filter *filter)
+{
+	/* These bytes are not mapped to any character in ISO-8859-7 */
+	if (c == 0xAE || c == 0xD2 || c == 0xFF)
+		filter->status = 1;
+	return c;
+}