diff --git a/dlls/oleaut32/tmarshal.c b/dlls/oleaut32/tmarshal.c
index b25cc4db2b5..b4c099dab08 100644
--- a/dlls/oleaut32/tmarshal.c
+++ b/dlls/oleaut32/tmarshal.c
@@ -86,6 +86,7 @@ xbuf_resize(marshal_state *buf, DWORD newsize)
         if(!buf->base)
             return E_OUTOFMEMORY;
     }
+    buf->size = newsize;
     return S_OK;
 }