diff --git a/src/nfc/tags/rw_i93.cc b/src/nfc/tags/rw_i93.cc
index a00a649..5d75605 100644
--- a/src/nfc/tags/rw_i93.cc
+++ b/src/nfc/tags/rw_i93.cc
@@ -2123,6 +2123,12 @@
       "sub_state:%s (0x%x)",
       rw_i93_get_sub_state_name(p_i93->sub_state).c_str(), p_i93->sub_state);
 
+  if (length == 0 || p_i93->block_size > I93_MAX_BLOCK_LENGH) {
+    android_errorWriteLog(0x534e4554, "122320256");
+    rw_i93_handle_error(NFC_STATUS_FAILED);
+    return;
+  }
+
   STREAM_TO_UINT8(flags, p);
   length--;
 
@@ -2147,6 +2153,12 @@
       /* get offset of length field */
       length_offset = (p_i93->ndef_tlv_start_offset + 1) % p_i93->block_size;
 
+      if (length < length_offset) {
+        android_errorWriteLog(0x534e4554, "122320256");
+        rw_i93_handle_error(NFC_STATUS_FAILED);
+        return;
+      }
+
       /* set length to zero */
       *(p + length_offset) = 0x00;
 
@@ -2160,6 +2172,11 @@
 
         /* write the first part of NDEF in the same block */
         for (; xx < p_i93->block_size; xx++) {
+          if (xx > length || p_i93->rw_length > p_i93->ndef_length) {
+            android_errorWriteLog(0x534e4554, "122320256");
+            rw_i93_handle_error(NFC_STATUS_FAILED);
+            return;
+          }
           if (p_i93->rw_length < p_i93->ndef_length) {
             *(p + xx) = *(p_i93->p_update_data + p_i93->rw_length++);
           } else {
@@ -2306,6 +2323,12 @@
 
           /* update length field within the read block */
           for (xx = length_offset; xx < p_i93->block_size; xx++) {
+            if (xx > length) {
+              android_errorWriteLog(0x534e4554, "122320256");
+              rw_i93_handle_error(NFC_STATUS_FAILED);
+              return;
+            }
+
             if (p_i93->rw_length == 3)
               *(p + xx) = 0xFF;
             else if (p_i93->rw_length == 2)