diff --git a/xdiff/xprepare.c b/xdiff/xprepare.c
index 5ffcf996f046136eaaf3fc9657810dfae0bed4ab..13b55aba7441bc84d2c5c075110e9ef798ba18f8 100644
--- a/xdiff/xprepare.c
+++ b/xdiff/xprepare.c
@@ -301,6 +301,7 @@ int xdl_prepare_env(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
 
 		xdl_free_ctx(&xe->xdf2);
 		xdl_free_ctx(&xe->xdf1);
+		xdl_free_classifier(&cf);
 		return -1;
 	}