diff --git a/tests/fuzz/fd-fuzz.cpp b/tests/fuzz/fd-fuzz.cpp
index 9049ab8..258c27e 100644
--- a/tests/fuzz/fd-fuzz.cpp
+++ b/tests/fuzz/fd-fuzz.cpp
@@ -5,6 +5,8 @@
 #undef NDEBUG
 #endif
 
+#include "msgbuf.hpp"
+
 #include <libpldm/base.h>
 #include <libpldm/firmware_fd.h>
 #include <libpldm/firmware_update.h>
@@ -17,7 +19,6 @@
 #include <vector>
 
 #include "array.h"
-#include "msgbuf.h"
 
 /* Avoid out-of-memory, and
  * avoid wasting time on inputs larger than MCTP message limits */
@@ -48,7 +49,7 @@
 
 struct fuzz_ops_ctx
 {
-    struct pldm_msgbuf* fuzz_ctrl;
+    struct pldm_msgbuf_ro* fuzz_ctrl;
 
     /* Details of in-progress update, for consistency checking */
     bool current_update;
@@ -64,7 +65,7 @@
 /* Returns true with roughly `percent` chance */
 static bool fuzz_chance(struct fuzz_ops_ctx* ctx, uint8_t percent)
 {
-    uint8_t v;
+    uint8_t v = 0;
     assert(percent <= 100);
     int rc = pldm_msgbuf_extract_uint8(ctx->fuzz_ctrl, v);
     if (rc != 0)
@@ -368,8 +369,8 @@
 
 extern "C" int LLVMFuzzerTestOneInput(uint8_t* input, size_t len)
 {
-    PLDM_MSGBUF_DEFINE_P(fuzzproto);
-    PLDM_MSGBUF_DEFINE_P(fuzzctrl);
+    PLDM_MSGBUF_RO_DEFINE_P(fuzzproto);
+    PLDM_MSGBUF_RO_DEFINE_P(fuzzctrl);
     int rc;
 
     /* Split input into two parts. First FUZZCTRL_SIZE (0x400 bytes currently)
@@ -397,7 +398,7 @@
     while (true)
     {
         /* Arbitrary length send buffer */
-        uint32_t send_len;
+        uint32_t send_len = 0;
         rc = pldm_msgbuf_extract_uint32(fuzzctrl, send_len);
         if (rc)
         {