diff --git a/src/mux/muxread.c b/src/mux/muxread.c

index fbe9f05..ea07dbf 100644

--- a/src/mux/muxread.c

+++ b/src/mux/muxread.c

@@ -264,6 +264,7 @@

         chunk_list = MuxGetChunkListFromId(mux, id);  // List to add this chunk.

         if (ChunkSetNth(&chunk, chunk_list, 0) != WEBP_MUX_OK) goto Err;

         if (id == WEBP_CHUNK_VP8X) {  // grab global specs

+          if (data_size < CHUNK_HEADER_SIZE + VP8X_CHUNK_SIZE) goto Err;

           mux->canvas_width_ = GetLE24(data + 12) + 1;

           mux->canvas_height_ = GetLE24(data + 15) + 1;

         }