diff --git a/projects/libprotobuf-mutator/build.sh b/projects/libprotobuf-mutator/build.sh
index a984510c7..c8e18b41a 100755
--- a/projects/libprotobuf-mutator/build.sh
+++ b/projects/libprotobuf-mutator/build.sh
@@ -22,6 +22,7 @@ mkdir -p build
 pushd build
 rm -rf *
 cmake .. -GNinja -DCMAKE_BUILD_TYPE=Release \
+    -DLIB_PROTO_MUTATOR_DOWNLOAD_PROTOBUF=ON \
     -DLIB_PROTO_MUTATOR_FUZZER_LIBRARIES=FuzzingEngine
 ninja libxml2_example expat_example
 cp -f examples/libxml2/libxml2_example $OUT/