diff --git a/tests/kdc/krb5.conf.in b/tests/kdc/krb5.conf.in
index 50f2e32c7..a8cb0ac41 100644
--- a/tests/kdc/krb5.conf.in
+++ b/tests/kdc/krb5.conf.in
@@ -3,6 +3,7 @@
 [libdefaults]
 	default_realm = TEST.H5L.SE
 	no-addresses = TRUE
+	allow_weak_crypto = @WEAK@
 
 [appdefaults]
 	pkinit_anchors = FILE:@srcdir@/../../lib/hx509/data/ca.crt