diff --git a/dlls/wbemprox/table.c b/dlls/wbemprox/table.c
index 34b09bc872f..ab386efa06b 100644
--- a/dlls/wbemprox/table.c
+++ b/dlls/wbemprox/table.c
@@ -178,7 +178,7 @@ BSTR get_value_bstr( const struct table *table, UINT row, UINT column )
         if (!val) return NULL;
         len = lstrlenW( (const WCHAR *)(INT_PTR)val ) + 2;
         if (!(ret = SysAllocStringLen( NULL, len ))) return NULL;
-        swprintf( ret, len, L"\"%s\"", (const WCHAR *)(INT_PTR)val );
+        swprintf( ret, len + 1, L"\"%s\"", (const WCHAR *)(INT_PTR)val );
         return ret;
 
     case CIM_SINT16: