diff --git a/src/qcbor_decode.c b/src/qcbor_decode.c
index 799fff2..56f15f7 100644
--- a/src/qcbor_decode.c
+++ b/src/qcbor_decode.c
@@ -4131,6 +4131,11 @@
       return;
    }
 
+   if(Item.uDataAlloc) {
+      pMe->uLastError = QCBOR_ERR_CANNOT_ENTER_ALLOCATED_STRING;
+      return;
+   }
+
    pMe->uLastError = (uint8_t)QCBORDecode_Private_EnterBstrWrapped(pMe,
                                                                   &Item,
                                                                    uTagRequirement,