diff --git a/src/core/tsi/fake_transport_security.cc b/src/core/tsi/fake_transport_security.cc
index 98c073779b0d2..21c29397d2433 100644
--- a/src/core/tsi/fake_transport_security.cc
+++ b/src/core/tsi/fake_transport_security.cc
@@ -191,6 +191,7 @@ static tsi_result tsi_fake_frame_decode(const unsigned char* incoming_bytes,
     frame->allocated_size = TSI_FAKE_FRAME_INITIAL_ALLOCATED_SIZE;
     frame->data =
         static_cast<unsigned char*>(gpr_malloc(frame->allocated_size));
+    memset(frame->data, 0xab, frame->allocated_size);
   }
 
   if (frame->offset < TSI_FAKE_FRAME_HEADER_SIZE) {