diff --git a/sshkey.c b/sshkey.c
index c8e9a6adb..514829299 100644
--- a/sshkey.c
+++ b/sshkey.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshkey.c,v 1.117 2021/07/05 01:21:07 dtucker Exp $ */
+/* $OpenBSD: sshkey.c,v 1.118 2021/07/12 06:08:57 dtucker Exp $ */
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  * Copyright (c) 2008 Alexander von Gernler.  All rights reserved.
@@ -3166,28 +3166,16 @@ size_t
 sshkey_format_cert_validity(const struct sshkey_cert *cert, char *s, size_t l)
 {
 	char from[32], to[32], ret[128];
-	time_t tt;
-	struct tm *tm;
 
 	*from = *to = '\0';
 	if (cert->valid_after == 0 &&
 	    cert->valid_before == 0xffffffffffffffffULL)
 		return strlcpy(s, "forever", l);
 
-	if (cert->valid_after != 0) {
-		/* XXX revisit INT_MAX in 2038 :) */
-		tt = cert->valid_after > INT_MAX ?
-		    INT_MAX : cert->valid_after;
-		tm = localtime(&tt);
-		strftime(from, sizeof(from), "%Y-%m-%dT%H:%M:%S", tm);
-	}
-	if (cert->valid_before != 0xffffffffffffffffULL) {
-		/* XXX revisit INT_MAX in 2038 :) */
-		tt = cert->valid_before > INT_MAX ?
-		    INT_MAX : cert->valid_before;
-		tm = localtime(&tt);
-		strftime(to, sizeof(to), "%Y-%m-%dT%H:%M:%S", tm);
-	}
+	if (cert->valid_after != 0)
+		format_absolute_time(cert->valid_after, from, sizeof(from));
+	if (cert->valid_before != 0xffffffffffffffffULL)
+		format_absolute_time(cert->valid_before, to, sizeof(to));
 
 	if (cert->valid_after == 0)
 		snprintf(ret, sizeof(ret), "before %s", to);