diff --git a/src/hb-ot-cff1-table.hh b/src/hb-ot-cff1-table.hh
index f51e33173..9d3f4b249 100644
--- a/src/hb-ot-cff1-table.hh
+++ b/src/hb-ot-cff1-table.hh
@@ -1176,7 +1176,8 @@ struct cff1
 	  if (unlikely (!font_interp.interpret (*font)))   goto fail;
 	  PRIVDICTVAL *priv = &privateDicts[i];
 	  const hb_ubytes_t privDictStr = StructAtOffsetOrNull<UnsizedByteStr> (cff, font->privateDictInfo.offset, sc, font->privateDictInfo.size).as_ubytes (font->privateDictInfo.size);
-	  if (unlikely (privDictStr == (const unsigned char *) &Null (UnsizedByteStr))) goto fail;
+	  if (unlikely (font->privateDictInfo.size &&
+			privDictStr == (const unsigned char *) &Null (UnsizedByteStr))) goto fail;
 	  num_interp_env_t env2 (privDictStr);
 	  dict_interpreter_t<PRIVOPSET, PRIVDICTVAL> priv_interp (env2);
 	  priv->init ();
@@ -1191,7 +1192,8 @@ struct cff1
 	PRIVDICTVAL *priv = &privateDicts[0];
 
 	const hb_ubytes_t privDictStr = StructAtOffsetOrNull<UnsizedByteStr> (cff, font->privateDictInfo.offset, sc, font->privateDictInfo.size).as_ubytes (font->privateDictInfo.size);
-	if (unlikely (privDictStr == (const unsigned char *) &Null (UnsizedByteStr))) goto fail;
+	if (font->privateDictInfo.size &&
+	    unlikely (privDictStr == (const unsigned char *) &Null (UnsizedByteStr))) goto fail;
 	num_interp_env_t env (privDictStr);
 	dict_interpreter_t<PRIVOPSET, PRIVDICTVAL> priv_interp (env);
 	priv->init ();
diff --git a/src/hb-ot-cff2-table.hh b/src/hb-ot-cff2-table.hh
index 83b1e2b81..f3b80a630 100644
--- a/src/hb-ot-cff2-table.hh
+++ b/src/hb-ot-cff2-table.hh
@@ -458,7 +458,8 @@ struct cff2
 	if (unlikely (!font_interp.interpret (*font))) goto fail;
 
 	const hb_ubytes_t privDictStr = StructAtOffsetOrNull<UnsizedByteStr> (cff2, font->privateDictInfo.offset, sc, font->privateDictInfo.size).as_ubytes (font->privateDictInfo.size);
-	if (unlikely (privDictStr == (const unsigned char *) &Null (UnsizedByteStr))) goto fail;
+	if (unlikely (font->privateDictInfo.size &&
+		      privDictStr == (const unsigned char *) &Null (UnsizedByteStr))) goto fail;
 	cff2_priv_dict_interp_env_t env2 (privDictStr);
 	dict_interpreter_t<PRIVOPSET, PRIVDICTVAL, cff2_priv_dict_interp_env_t> priv_interp (env2);
 	privateDicts[i].init ();