diff --git a/src/helpers/AdvertDataHelpers.cpp b/src/helpers/AdvertDataHelpers.cpp
index 998733ae04..85172762fc 100644
--- a/src/helpers/AdvertDataHelpers.cpp
+++ b/src/helpers/AdvertDataHelpers.cpp
@@ -37,13 +37,16 @@
   
     int i = 1;
     if (_flags & ADV_LATLON_MASK) {
+      if (i + 8 > app_data_len) return;
       memcpy(&_lat, &app_data[i], 4); i += 4;
       memcpy(&_lon, &app_data[i], 4); i += 4;
     }
     if (_flags & ADV_FEAT1_MASK) {
+      if (i + 2 > app_data_len) return;
       memcpy(&_extra1, &app_data[i], 2); i += 2;
     }
     if (_flags & ADV_FEAT2_MASK) {
+      if (i + 2 > app_data_len) return;
       memcpy(&_extra2, &app_data[i], 2); i += 2;
     }