diff --git a/projects/zlib/zlib_uncompress3_fuzzer.cc b/projects/zlib/zlib_uncompress3_fuzzer.cc
index 4756d05952d7..e0f6da7ca845 100644
--- a/projects/zlib/zlib_uncompress3_fuzzer.cc
+++ b/projects/zlib/zlib_uncompress3_fuzzer.cc
@@ -30,6 +30,8 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   uLong multiplier1 = size ? (--size, *data++) : 1;
 
   uLongf buffer_length = static_cast<uLongf>(basesz * multiplier0 * multiplier1);
+  if (buffer_length > sizeof(buffer))
+    buffer_length = sizeof(buffer);
   uLong buf_size = static_cast<uLong>(size);
   // Ignore return code.
   uncompress2(buffer, &buffer_length, data, &buf_size);