diff --git a/testing/fuzzers/pdf_cmap_fuzzer.cc b/testing/fuzzers/pdf_cmap_fuzzer.cc
index 7d35fd0..c827b7c 100644
--- a/testing/fuzzers/pdf_cmap_fuzzer.cc
+++ b/testing/fuzzers/pdf_cmap_fuzzer.cc
@@ -8,6 +8,9 @@
 #include "third_party/base/span.h"
 
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  if (size > 256 * 1024)
+    return 0;
+
   pdfium::MakeRetain<CPDF_CMap>()->LoadEmbedded(pdfium::make_span(data, size));
   return 0;
 }