untrusted comment: verify with openbsd-68-base.pub
RWQZj25CSG5R2kYcXPP/VEh+5ekxHzMQ2cH06oeYJ4VReXkn1RSQWn8OWoggkNeXYFwsyJWMweXJenlVFojhtLyimMu0vDc5ngs=

OpenBSD 6.8 errata 017, March 12, 2021:

A TLS client using session resumption may cause a use-after-free.

Apply by doing:
    signify -Vep /etc/signify/openbsd-68-base.pub -x 017_libssl.patch.sig \
        -m - | (cd /usr/src && patch -p0)

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

Index: lib/libssl/s3_lib.c
===================================================================
RCS file: /home/cvs/src/lib/libssl/s3_lib.c,v
retrieving revision 1.198
diff -u -p -r1.198 s3_lib.c
--- lib/libssl/s3_lib.c	17 Sep 2020 15:42:14 -0000	1.198
+++ lib/libssl/s3_lib.c	9 Mar 2021 18:50:53 -0000
@@ -1577,6 +1577,10 @@ ssl3_free(SSL *s)
 
 	free(S3I(s)->alpn_selected);
 
+	/* Clear reference to sequence numbers. */
+	tls12_record_layer_clear_read_state(s->internal->rl);
+	tls12_record_layer_clear_write_state(s->internal->rl);
+
 	freezero(S3I(s), sizeof(*S3I(s)));
 	freezero(s->s3, sizeof(*s->s3));
 
@@ -1648,6 +1652,11 @@ ssl3_clear(SSL *s)
 
 	s->internal->packet_length = 0;
 	s->version = TLS1_VERSION;
+
+	tls12_record_layer_set_read_seq_num(s->internal->rl,
+	    S3I(s)->read_sequence);
+	tls12_record_layer_set_write_seq_num(s->internal->rl,
+	    S3I(s)->write_sequence);
 
 	S3I(s)->hs.state = SSL_ST_BEFORE|((s->server) ? SSL_ST_ACCEPT : SSL_ST_CONNECT);
 }
Index: lib/libssl/ssl_lib.c
===================================================================
RCS file: /home/cvs/src/lib/libssl/ssl_lib.c,v
retrieving revision 1.234.4.1
diff -u -p -r1.234.4.1 ssl_lib.c
--- lib/libssl/ssl_lib.c	3 Feb 2021 07:06:13 -0000	1.234.4.1
+++ lib/libssl/ssl_lib.c	9 Mar 2021 18:50:53 -0000
@@ -253,6 +253,8 @@ SSL_new(SSL_CTX *ctx)
 		goto err;
 	if ((s->internal = calloc(1, sizeof(*s->internal))) == NULL)
 		goto err;
+	if ((s->internal->rl = tls12_record_layer_new()) == NULL)
+		goto err;
 
 	s->internal->min_version = ctx->internal->min_version;
 	s->internal->max_version = ctx->internal->max_version;
@@ -339,9 +341,6 @@ SSL_new(SSL_CTX *ctx)
 	s->method = ctx->method;
 
 	if (!s->method->internal->ssl_new(s))
-		goto err;
-
-	if ((s->internal->rl = tls12_record_layer_new()) == NULL)
 		goto err;
 
 	s->references = 1;