diff --git a/src/net.cpp b/src/net.cpp
index 9aafee03e4ee..58863db74812 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -2206,6 +2206,14 @@ int Extractor::input(int blob_index, const Mat& in)
     if (blob_index < 0 || blob_index >= (int)d->blob_mats.size())
         return -1;
 
+    const Mat& shape = d->net->blobs()[blob_index].shape;
+    if (shape.total())
+    {
+        const Mat& in_shape = in.shape();
+        if (shape.dims != in_shape.dims || shape.w != in_shape.w || shape.h != in_shape.h || shape.d != in_shape.d || shape.c != in_shape.c)
+            return -1;
+    }
+
     d->blob_mats[blob_index] = in;
 
     return 0;