diff --git a/src/wp_dh_kmgmt.c b/src/wp_dh_kmgmt.c
index 5dc1ffc3..51368614 100644
--- a/src/wp_dh_kmgmt.c
+++ b/src/wp_dh_kmgmt.c
@@ -807,7 +807,7 @@ static int wp_dh_get_params(wp_Dh* dh, OSSL_PARAM params[])
         p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_PRIV_KEY);
         if (p != NULL) {
             if (p->data == NULL) {
-                p->return_size = dh->pubSz;
+                p->return_size = dh->privSz;
             }
             else if (p->data_type == OSSL_PARAM_UNSIGNED_INTEGER) {
                 if (p->data_size < dh->privSz) {
@@ -826,9 +826,15 @@ static int wp_dh_get_params(wp_Dh* dh, OSSL_PARAM params[])
             }
         }
     }
-    if (ok && (!wp_params_set_octet_string_be(params, OSSL_PKEY_PARAM_PRIV_KEY,
-            dh->priv, dh->privSz))) {
-        ok = 0;
+    if (ok) {
+        /* Only call if we haven't already handled OSSL_PKEY_PARAM_PRIV_KEY */
+        p = OSSL_PARAM_locate(params, OSSL_PKEY_PARAM_PRIV_KEY);
+        if (p == NULL || p->data != NULL) {
+            if (!wp_params_set_octet_string_be(params, OSSL_PKEY_PARAM_PRIV_KEY,
+                    dh->priv, dh->privSz)) {
+                ok = 0;
+            }
+        }
     }
     if (ok && (!wp_dh_get_params_encoded_public_key(dh, params))) {
         ok = 0;
diff --git a/test/test_dh.c b/test/test_dh.c
index 8874a870..bc9fce29 100644
--- a/test/test_dh.c
+++ b/test/test_dh.c
@@ -508,6 +508,9 @@ int test_dh_get_params(void *data)
             for (int j = 0; j < 2; j++) {
                 if (j == 0) {
                     mode = "Null data";
+                    paramsWolfProvider[0] = gettableParams[i];
+                    paramsWolfProvider[0].data = NULL;
+                    paramsWolfProvider[0].data_size = 0;
                 }
                 else {
                     mode = "Buffer data";