diff
--- a/key_instantiate_and_link.c
+++ b/key_instantiate_and_link.c
@@ -41,5 +41,6 @@
 		ret = key->type->instantiate(key, prep);
 		if (ret == 0) {
 
+			prep->expiry = min(prep->expiry, MAX_EXPIRY_VALUE); // Sanitize input
 			key_set_expiry(key, prep->expiry);
 error:

