diff --git a/library/bignum.c b/library/bignum.c
index 3ec6ad0..0e969d5 100644
--- a/library/bignum.c
+++ b/library/bignum.c
@@ -1599,7 +1599,7 @@
 
     mpi_free( &W[1] ); mpi_free( &T ); mpi_free( &Apos );
 
-    if( _RR == NULL )
+    if( _RR == NULL || _RR->p == NULL )
         mpi_free( &RR );
 
     return( ret );