diff --git a/Surface_mesh_parameterization/include/CGAL/Surface_mesh_parameterization/internal/validity.h b/Surface_mesh_parameterization/include/CGAL/Surface_mesh_parameterization/internal/validity.h
index 9a0c2e438ab..9b41bb25649 100644
--- a/Surface_mesh_parameterization/include/CGAL/Surface_mesh_parameterization/internal/validity.h
+++ b/Surface_mesh_parameterization/include/CGAL/Surface_mesh_parameterization/internal/validity.h
@@ -272,10 +272,10 @@ bool is_one_to_one_mapping(const TriangleMesh& mesh,
     const Point_2& p1 = get(uvmap, vd1);
     const Point_2& p2 = get(uvmap, vd2);
 
-    NT bx[2] = { (std::min)(p0[0], p1[0]),
-                 (std::min)(p0[1], p1[1]) };
-    NT by[2] = { (std::max)(p0[0], p1[0]),
-                 (std::max)(p0[1], p1[1]) };
+    NT bx[2] = { (std::min)(p0[0], (std::min)(p1[0], p2[0])),
+                 (std::min)(p0[1], (std::min)(p1[1], p2[1])) };
+    NT by[2] = { (std::max)(p0[0], (std::max)(p1[0], p2[0])),
+                 (std::max)(p0[1], (std::max)(p1[1], p2[1])) };
     boxes.push_back(Box(bx, by, fd));
   }