untrusted comment: signature from openbsd 6.3 base secret key
RWRxzbLwAd76ZYAfG6MFoKJNzrusDrl83pEWqz7tgRZC1FGX8MkgRvADnj7DbU/6EsF63QBjvDGt8H9v9XjexGsoFIuTK8ODMQo=

OpenBSD 6.3 errata 002, April 21, 2018:

Additional data is inadvertently removed when private keys are cleared from
TLS configuration, which can prevent OCSP from functioning correctly.

Apply by doing:
   signify -Vep /etc/signify/openbsd-63-base.pub -x 002_libtls.patch.sig \
       -m - | (cd /usr/src && patch -p0)

And then rebuild and install libssl:
   cd /usr/src/lib/libtls
   make obj
   make
   make install

Index: lib/libtls/tls_config.c
===================================================================
RCS file: /cvs/src/lib/libtls/tls_config.c,v
retrieving revision 1.51
retrieving revision 1.51.2.1
diff -u -p -r1.51 -r1.51.2.1
--- lib/libtls/tls_config.c     20 Mar 2018 15:40:10 -0000      1.51
+++ lib/libtls/tls_config.c     18 Apr 2018 16:29:11 -0000      1.51.2.1
@@ -189,10 +189,7 @@ tls_config_clear_keys(struct tls_config
       struct tls_keypair *kp;

       for (kp = config->keypair; kp != NULL; kp = kp->next)
-               tls_keypair_clear(kp);
-
-       tls_config_set_ca_mem(config, NULL, 0);
-       tls_config_set_crl_mem(config, NULL, 0);
+               tls_keypair_clear_key(kp);
}

int
Index: lib/libtls/tls_internal.h
===================================================================
RCS file: /cvs/src/lib/libtls/tls_internal.h,v
retrieving revision 1.71
retrieving revision 1.71.2.1
diff -u -p -r1.71 -r1.71.2.1
--- lib/libtls/tls_internal.h   19 Mar 2018 16:34:47 -0000      1.71
+++ lib/libtls/tls_internal.h   18 Apr 2018 16:29:11 -0000      1.71.2.1
@@ -199,6 +199,7 @@ int tls_set_mem(char **_dest, size_t *_d
int tls_set_string(const char **_dest, const char *_src);

struct tls_keypair *tls_keypair_new(void);
+void tls_keypair_clear_key(struct tls_keypair *_keypair);
void tls_keypair_clear(struct tls_keypair *_keypair);
void tls_keypair_free(struct tls_keypair *_keypair);
int tls_keypair_set_cert_file(struct tls_keypair *_keypair,
Index: lib/libtls/tls_keypair.c
===================================================================
RCS file: /cvs/src/lib/libtls/tls_keypair.c,v
retrieving revision 1.5
retrieving revision 1.5.2.1
diff -u -p -r1.5 -r1.5.2.1
--- lib/libtls/tls_keypair.c    10 Feb 2018 04:57:35 -0000      1.5
+++ lib/libtls/tls_keypair.c    18 Apr 2018 16:29:11 -0000      1.5.2.1
@@ -29,7 +29,7 @@ tls_keypair_new(void)
       return calloc(1, sizeof(struct tls_keypair));
}

-static void
+void
tls_keypair_clear_key(struct tls_keypair *keypair)
{
       freezero(keypair->key_mem, keypair->key_len);