Also stop processing input stream
diff --git a/test/core/end2end/fuzzers/api_fuzzer.cc b/test/core/end2end/fuzzers/api_fuzzer.cc
index 884cbdb..43c9fa1 100644
--- a/test/core/end2end/fuzzers/api_fuzzer.cc
+++ b/test/core/end2end/fuzzers/api_fuzzer.cc
@@ -283,6 +283,7 @@
 static grpc_call_credentials* read_call_creds(input_stream* inp, int depth) {
   if (depth > 64) {
     // prevent creating infinitely deep call creds
+    end(inp);
     return nullptr;
   }
   switch (next_byte(inp)) {