diff --git a/c/src/ml-api-inference-single.c b/c/src/ml-api-inference-single.c
index 03df6326..c6638f09 100644
--- a/c/src/ml-api-inference-single.c
+++ b/c/src/ml-api-inference-single.c
@@ -1997,6 +1997,30 @@ __ml_validate_model_file (const char *const *model,
   return ML_ERROR_NONE;
 }
 
+/**
+ * @brief Internal helper to check if the file has one of the valid extensions.
+ * @return TRUE if valid, FALSE otherwise.
+ */
+static gboolean
+_is_valid_extension (const char *filename, const char *const *valid_exts)
+{
+  const char *dot;
+
+  if (!filename || !valid_exts)
+    return FALSE;
+
+  dot = strrchr (filename, '.');
+  if (!dot)
+    return FALSE;
+
+  for (; *valid_exts; valid_exts++) {
+    if (g_ascii_strcasecmp (dot, *valid_exts) == 0)
+      return TRUE;
+  }
+
+  return FALSE;
+}
+
 /**
  * @brief Validates the nnfw model file.
  * @since_tizen 5.5
@@ -2014,9 +2038,7 @@ _ml_validate_model_file (const char *const *model,
   int status = ML_ERROR_NONE;
   ml_nnfw_type_e detected = ML_NNFW_TYPE_ANY;
   gboolean is_dir = FALSE;
-  gchar *pos, *fw_name;
-  gchar **file_ext = NULL;
-  guint i;
+  gchar *fw_name;
 
   if (!nnfw)
     _ml_error_report_return (ML_ERROR_INVALID_PARAMETER,
@@ -2060,19 +2082,6 @@ _ml_validate_model_file (const char *const *model,
     goto done;
   }
 
-  /* Handle mismatched case, check file extension. */
-  file_ext = g_malloc0 (sizeof (char *) * (num_models + 1));
-  for (i = 0; i < num_models; i++) {
-    if ((pos = strrchr (model[i], '.')) == NULL) {
-      _ml_error_report ("The given model [%d]=\"%s\" has invalid extension.", i,
-          model[i]);
-      status = ML_ERROR_INVALID_PARAMETER;
-      goto done;
-    }
-
-    file_ext[i] = g_ascii_strdown (pos, -1);
-  }
-
   /** @todo Make sure num_models is correct for each nnfw type */
   switch (*nnfw) {
     case ML_NNFW_TYPE_NNFW:
@@ -2101,11 +2110,10 @@ _ml_validate_model_file (const char *const *model,
       status = ML_ERROR_NOT_SUPPORTED;
       break;
     case ML_NNFW_TYPE_VD_AIFW:
-      if (!g_str_equal (file_ext[0], ".nb") &&
-          !g_str_equal (file_ext[0], ".ncp") &&
-          !g_str_equal (file_ext[0], ".tvn") &&
-          !g_str_equal (file_ext[0], ".bin")) {
-        status = ML_ERROR_INVALID_PARAMETER;
+      {
+        const char *exts[] = { ".nb", ".ncp", ".tvn", ".bin", NULL };
+        if (!_is_valid_extension (model[0], exts))
+          status = ML_ERROR_INVALID_PARAMETER;
       }
       break;
     case ML_NNFW_TYPE_SNAP:
@@ -2116,20 +2124,20 @@ _ml_validate_model_file (const char *const *model,
       /* SNAP requires multiple files, set supported if model file exists. */
       break;
     case ML_NNFW_TYPE_ARMNN:
-      if (!g_str_equal (file_ext[0], ".caffemodel") &&
-          !g_str_equal (file_ext[0], ".tflite") &&
-          !g_str_equal (file_ext[0], ".pb") &&
-          !g_str_equal (file_ext[0], ".prototxt")) {
-        _ml_error_report
-            ("ARMNN accepts .caffemodel, .tflite, .pb, and .prototxt files only. Please support correct file extension. You have specified: \"%s\"",
-            file_ext[0]);
-        status = ML_ERROR_INVALID_PARAMETER;
+      {
+        const char *exts[] =
+            { ".caffemodel", ".tflite", ".pb", ".prototxt", NULL };
+        if (!_is_valid_extension (model[0], exts)) {
+          _ml_error_report ("Invalid extension for ARMNN: %s", model[0]);
+          status = ML_ERROR_INVALID_PARAMETER;
+        }
       }
       break;
     case ML_NNFW_TYPE_MXNET:
-      if (!g_str_equal (file_ext[0], ".params") &&
-          !g_str_equal (file_ext[0], ".json")) {
-        status = ML_ERROR_INVALID_PARAMETER;
+      {
+        const char *exts[] = { ".params", ".json", NULL };
+        if (!_is_valid_extension (model[0], exts))
+          status = ML_ERROR_INVALID_PARAMETER;
       }
       break;
     default:
@@ -2153,6 +2161,5 @@ _ml_validate_model_file (const char *const *model,
         model[0], num_models);
   }
 
-  g_strfreev (file_ext);
   return status;
 }