1 files changed, 7 insertions, 1 deletions

diff --git a/src/lib/libcrypto/bn/bn_print.c b/src/lib/libcrypto/bn/bn_print.c
index 466aeb3d64..18984d7d4f 100644
--- a/src/lib/libcrypto/bn/bn_print.c
+++ b/src/lib/libcrypto/bn/bn_print.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: bn_print.c,v 1.40 2023/07/06 14:37:39 tb Exp $ */
+/*      $OpenBSD: bn_print.c,v 1.41 2023/07/07 06:41:59 tb Exp $ */
 
 /*
  * Copyright (c) 2023 Theo Buehler <tb@openbsd.org>
@@ -102,6 +102,12 @@ bn_print_bignum(BIO *bio, const BIGNUM *bn, int indent)
                         if (BIO_printf(bio, "\n%*s", indent, "") <= 0)
                                 goto err;
                 }
+                /* First nibble has the high bit set. Insert leading 0 octet. */
+                if (octets == 1 && hi >= '8') {
+                        if (BIO_printf(bio, "00:") <= 0)
+                                goto err;
+                        octets++;
+                }
                 if (CBS_len(&cbs) == 0)
                         sep = "";
                 if (BIO_printf(bio, "%c%c%s", tolower(hi), tolower(lo), sep) <= 0)