diff --git a/expat/lib/xmltok.c b/expat/lib/xmltok.c
index 7fc00e89..0e9a18a2 100644
--- a/expat/lib/xmltok.c
+++ b/expat/lib/xmltok.c
@@ -84,7 +84,11 @@
 #define UTF8_INVALID3(p) \
   (((p)[2] & 0x80) == 0 \
   || \
-  ((*p) == 0xEF ? (p)[2] > 0xBD : ((p)[2] & 0xC0) == 0xC0) \
+  ((*p) == 0xEF && (p)[1] == 0xBF \
+    ? \
+    (p)[2] > 0xBD \
+    : \
+    ((p)[2] & 0xC0) == 0xC0) \
   || \
   ((*p) == 0xE0 \
     ? \