@@ -4,3 +4,5 @@ build/
 /python/*.egg-info
 /python/.eggs
 /python/tiny_obj_loader.h
+/tests/tester
+/tests/tester.dSYM
@@ -0,0 +1,2 @@
+vt 0 0
+f 1/-1 1/-1 1/-2
@@ -0,0 +1 @@
+f -4 -3 -2
@@ -858,6 +858,50 @@ void test_zero_face_idx_value_issue140() {
   TEST_CHECK(!err.empty());
 }
 
+void test_invalid_relative_vertex_index() {
+  tinyobj::attrib_t attrib;
+  std::vector<tinyobj::shape_t> shapes;
+  std::vector<tinyobj::material_t> materials;
+
+  std::string warn;
+  std::string err;
+  bool ret =
+      tinyobj::LoadObj(&attrib, &shapes, &materials, &warn, &err,
+                       "../models/invalid-relative-vertex-index.obj", gMtlBasePath);
+
+  if (!warn.empty()) {
+    std::cout << "WARN: " << warn << std::endl;
+  }
+
+  if (!err.empty()) {
+    std::cerr << "ERR: " << err << std::endl;
+  }
+  TEST_CHECK(false == ret);
+  TEST_CHECK(!err.empty());
+}
+
+void test_invalid_texture_vertex_index() {
+  tinyobj::attrib_t attrib;
+  std::vector<tinyobj::shape_t> shapes;
+  std::vector<tinyobj::material_t> materials;
+
+  std::string warn;
+  std::string err;
+  bool ret =
+      tinyobj::LoadObj(&attrib, &shapes, &materials, &warn, &err,
+                       "../models/invalid-relative-texture-vertex-index.obj", gMtlBasePath);
+
+  if (!warn.empty()) {
+    std::cout << "WARN: " << warn << std::endl;
+  }
+
+  if (!err.empty()) {
+    std::cerr << "ERR: " << err << std::endl;
+  }
+  TEST_CHECK(false == ret);
+  TEST_CHECK(!err.empty());
+}
+
 void test_texture_name_whitespace_issue145() {
   tinyobj::attrib_t attrib;
   std::vector<tinyobj::shape_t> shapes;
@@ -1467,4 +1511,8 @@ TEST_LIST = {
      test_mtl_filename_with_whitespace_issue46},
     {"test_face_missing_issue295",
      test_face_missing_issue295},
+    {"test_invalid_relative_vertex_index",
+     test_invalid_relative_vertex_index},
+    {"test_invalid_texture_vertex_index",
+     test_invalid_texture_vertex_index},
     {NULL, NULL}};
@@ -835,6 +835,9 @@ static inline bool fixIndex(int idx, int n, int *ret, bool allow_zero, const war
 
   if (idx < 0) {
     (*ret) = n + idx;  // negative value = relative
+    if((*ret) < 0){
+      return false;  // invalid relative index
+    }
     return true;
   }
 
@@ -2782,7 +2785,7 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
                          static_cast<int>(vn.size() / 3),
                          static_cast<int>(vt.size() / 2), &vi, context)) {
           if (err) {
-            (*err) += "Failed to parse `f' line (e.g. a zero value for vertex index. Line " +
+            (*err) += "Failed to parse `f' line (e.g. a zero value for vertex index or invalid relative vertex index). Line " +
                 toString(line_num) + ").\n";
           }
           return false;