diff --git a/src/hb-ot-cff1-table.hh b/src/hb-ot-cff1-table.hh
index 7fbda905e..51cc84694 100644
--- a/src/hb-ot-cff1-table.hh
+++ b/src/hb-ot-cff1-table.hh
@@ -110,7 +110,8 @@ struct Encoding1 {
     {
       if (glyph <= ranges[i].nLeft)
       {
-	return (hb_codepoint_t)ranges[i].first + glyph;
+	hb_codepoint_t code = (hb_codepoint_t)ranges[i].first + glyph;
+	return (likely (code < 0x100)? code: CFF_UNDEF_CODE);
       }
       glyph -= (ranges[i].nLeft + 1);
     }
diff --git a/test/fuzzing/fonts/clusterfuzz-testcase-minimized-hb-subset-fuzzer-5923632099885056 b/test/fuzzing/fonts/clusterfuzz-testcase-minimized-hb-subset-fuzzer-5923632099885056
new file mode 100644
index 000000000..0a3c6df0e
Binary files /dev/null and b/test/fuzzing/fonts/clusterfuzz-testcase-minimized-hb-subset-fuzzer-5923632099885056 differ