diff -urNp a/python/hawkey/exception-py.hpp b/python/hawkey/exception-py.hpp
--- a/python/hawkey/exception-py.hpp	2020-06-02 17:41:46.000000000 +0800
+++ b/python/hawkey/exception-py.hpp	2020-08-31 10:28:07.000000000 +0800
@@ -37,7 +37,7 @@ PyObject *op_error2exc(const GError *err
 int ret2e(int ret, const char *msg);
 
 #define CATCH_TO_PYTHON_RET(RET) catch (const libdnf::Error& e) { \
-    PyErr_Format(HyExc_Exception, e.what());                      \
+    PyErr_Format(HyExc_Exception, "%s", e.what());                      \
     return RET;                                                   \
 }