diff --git a/bson/_cbsonmodule.c b/bson/_cbsonmodule.c
index 3e9d5ecc26..331e115ef4 100644
--- a/bson/_cbsonmodule.c
+++ b/bson/_cbsonmodule.c
@@ -279,7 +279,7 @@ static PyObject* datetime_from_millis(long long millis) {
      * micros = diff * 1000                       111000
      * Resulting in datetime(1, 1, 1, 1, 1, 1, 111000) -- the expected result
      */
-    PyObject* datetime;
+    PyObject* datetime = NULL;
     int diff = (int)(((millis % 1000) + 1000) % 1000);
     int microseconds = diff * 1000;
     Time64_T seconds = (millis - diff) / 1000;
@@ -1790,7 +1790,7 @@ static PyObject* _cbson_dict_to_bson(PyObject* self, PyObject* args) {
     PyObject* result;
     unsigned char check_keys;
     unsigned char top_level = 1;
-    PyObject* options_obj;
+    PyObject* options_obj = NULL;
     codec_options_t options;
     buffer_t buffer;
     PyObject* raw_bson_document_bytes_obj;
@@ -2620,7 +2620,7 @@ static PyObject* _cbson_element_to_dict(PyObject* self, PyObject* args) {
     /* TODO: Support buffer protocol */
     char* string;
     PyObject* bson;
-    PyObject* options_obj;
+    PyObject* options_obj = NULL;
     codec_options_t options;
     unsigned position;
     unsigned max;
@@ -2732,7 +2732,7 @@ static PyObject* _cbson_bson_to_dict(PyObject* self, PyObject* args) {
     int32_t size;
     Py_ssize_t total_size;
     const char* string;
-    PyObject* bson;
+    PyObject* bson = NULL;
     codec_options_t options;
     PyObject* result = NULL;
     PyObject* options_obj;
diff --git a/pymongo/_cmessagemodule.c b/pymongo/_cmessagemodule.c
index f95b949380..43549baa0e 100644
--- a/pymongo/_cmessagemodule.c
+++ b/pymongo/_cmessagemodule.c
@@ -540,7 +540,7 @@ _cbson_encode_batched_op_msg(PyObject* self, PyObject* args) {
     PyObject* ctx = NULL;
     PyObject* to_publish = NULL;
     PyObject* result = NULL;
-    PyObject* options_obj;
+    PyObject* options_obj = NULL;
     codec_options_t options;
     buffer_t buffer;
     struct module_state *state = GETSTATE(self);
@@ -597,7 +597,7 @@ _cbson_batched_op_msg(PyObject* self, PyObject* args) {
     PyObject* ctx = NULL;
     PyObject* to_publish = NULL;
     PyObject* result = NULL;
-    PyObject* options_obj;
+    PyObject* options_obj = NULL;
     codec_options_t options;
     buffer_t buffer;
     struct module_state *state = GETSTATE(self);
@@ -873,7 +873,7 @@ _cbson_encode_batched_write_command(PyObject* self, PyObject* args) {
     PyObject* ctx = NULL;
     PyObject* to_publish = NULL;
     PyObject* result = NULL;
-    PyObject* options_obj;
+    PyObject* options_obj = NULL;
     codec_options_t options;
     buffer_t buffer;
     struct module_state *state = GETSTATE(self);