diff --git a/krl.c b/krl.c
index e2efdf06..0d0f6953 100644
--- a/krl.c
+++ b/krl.c
@@ -674,6 +674,7 @@ revoked_certs_generate(struct revoked_certs *rc, struct sshbuf *buf)
 			break;
 		case KRL_SECTION_CERT_SERIAL_BITMAP:
 			if (rs->lo - bitmap_start > INT_MAX) {
+				r = SSH_ERR_INVALID_FORMAT;
 				error_f("insane bitmap gap");
 				goto out;
 			}
@@ -1059,6 +1060,7 @@ ssh_krl_from_blob(struct sshbuf *buf, struct ssh_krl **krlp)
 	}
 
 	if ((krl = ssh_krl_init()) == NULL) {
+		r = SSH_ERR_ALLOC_FAIL;
 		error_f("alloc failed");
 		goto out;
 	}
diff --git a/packet.c b/packet.c
index 486f8515..9dea2cfc 100644
--- a/packet.c
+++ b/packet.c
@@ -1864,6 +1864,14 @@ ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
 			if ((r = sshpkt_get_string_direct(ssh, &d, &len)) != 0)
 				return r;
 			DBG(debug("Received SSH2_MSG_PING len %zu", len));
+			if (!ssh->state->after_authentication) {
+				DBG(debug("Won't reply to PING in preauth"));
+				break;
+			}
+			if (ssh_packet_is_rekeying(ssh)) {
+				DBG(debug("Won't reply to PING during KEX"));
+				break;
+			}
 			if ((r = sshpkt_start(ssh, SSH2_MSG_PONG)) != 0 ||
 			    (r = sshpkt_put_string(ssh, d, len)) != 0 ||
 			    (r = sshpkt_send(ssh)) != 0)
diff --git a/ssh-agent.c b/ssh-agent.c
index 48973b2c..c27c5a95 100644
--- a/ssh-agent.c
+++ b/ssh-agent.c
@@ -1220,6 +1220,7 @@ parse_key_constraint_extension(struct sshbuf *m, char **sk_providerp,
 	    "restrict-destination-v00@openssh.com") == 0) {
 		if (*dcsp != NULL) {
 			error_f("%s already set", ext_name);
+			r = SSH_ERR_INVALID_FORMAT;
 			goto out;
 		}
 		if ((r = sshbuf_froms(m, &b)) != 0) {
@@ -1229,6 +1230,7 @@ parse_key_constraint_extension(struct sshbuf *m, char **sk_providerp,
 		while (sshbuf_len(b) != 0) {
 			if (*ndcsp >= AGENT_MAX_DEST_CONSTRAINTS) {
 				error_f("too many %s constraints", ext_name);
+				r = SSH_ERR_INVALID_FORMAT;
 				goto out;
 			}
 			*dcsp = xrecallocarray(*dcsp, *ndcsp, *ndcsp + 1,
@@ -1246,6 +1248,7 @@ parse_key_constraint_extension(struct sshbuf *m, char **sk_providerp,
 		}
 		if (*certs != NULL) {
 			error_f("%s already set", ext_name);
+			r = SSH_ERR_INVALID_FORMAT;
 			goto out;
 		}
 		if ((r = sshbuf_get_u8(m, &v)) != 0 ||
@@ -1257,6 +1260,7 @@ parse_key_constraint_extension(struct sshbuf *m, char **sk_providerp,
 		while (sshbuf_len(b) != 0) {
 			if (*ncerts >= AGENT_MAX_EXT_CERTS) {
 				error_f("too many %s constraints", ext_name);
+				r = SSH_ERR_INVALID_FORMAT;
 				goto out;
 			}
 			*certs = xrecallocarray(*certs, *ncerts, *ncerts + 1,
@@ -1757,6 +1761,7 @@ process_ext_session_bind(SocketEntry *e)
 	/* record new key/sid */
 	if (e->nsession_ids >= AGENT_MAX_SESSION_IDS) {
 		error_f("too many session IDs recorded");
+		r = -1;
 		goto out;
 	}
 	e->session_ids = xrecallocarray(e->session_ids, e->nsession_ids,
diff --git a/ssh-sk-client.c b/ssh-sk-client.c
index 321fe53a..06fad221 100644
--- a/ssh-sk-client.c
+++ b/ssh-sk-client.c
@@ -439,6 +439,7 @@ sshsk_load_resident(const char *provider_path, const char *device,
 		}
 		if ((srk = calloc(1, sizeof(*srk))) == NULL) {
 			error_f("calloc failed");
+			r = SSH_ERR_ALLOC_FAIL;
 			goto out;
 		}
 		srk->key = key;
@@ -450,6 +451,7 @@ sshsk_load_resident(const char *provider_path, const char *device,
 		if ((tmp = recallocarray(srks, nsrks, nsrks + 1,
 		    sizeof(*srks))) == NULL) {
 			error_f("recallocarray keys failed");
+			r = SSH_ERR_ALLOC_FAIL;
 			goto out;
 		}
 		debug_f("srks[%zu]: %s %s uidlen %zu", nsrks,
diff --git a/sshconnect2.c b/sshconnect2.c
index a69c4da1..1ee6000a 100644
--- a/sshconnect2.c
+++ b/sshconnect2.c
@@ -99,7 +99,7 @@ verify_host_key_callback(struct sshkey *hostkey, struct ssh *ssh)
 	    options.required_rsa_size)) != 0)
 		fatal_r(r, "Bad server host key");
 	if (verify_host_key(xxx_host, xxx_hostaddr, hostkey,
-	    xxx_conn_info) == -1)
+	    xxx_conn_info) != 0)
 		fatal("Host key verification failed.");
 	return 0;
 }
@@ -699,6 +699,7 @@ input_userauth_pk_ok(int type, u_int32_t seq, struct ssh *ssh)
 
 	if ((pktype = sshkey_type_from_name(pkalg)) == KEY_UNSPEC) {
 		debug_f("server sent unknown pkalg %s", pkalg);
+		r = SSH_ERR_INVALID_FORMAT;
 		goto done;
 	}
 	if ((r = sshkey_from_blob(pkblob, blen, &key)) != 0) {
@@ -709,6 +710,7 @@ input_userauth_pk_ok(int type, u_int32_t seq, struct ssh *ssh)
 		error("input_userauth_pk_ok: type mismatch "
 		    "for decoded key (received %d, expected %d)",
 		    key->type, pktype);
+		r = SSH_ERR_INVALID_FORMAT;
 		goto done;
 	}
 
@@ -728,6 +730,7 @@ input_userauth_pk_ok(int type, u_int32_t seq, struct ssh *ssh)
 		    SSH_FP_DEFAULT);
 		error_f("server replied with unknown key: %s %s",
 		    sshkey_type(key), fp == NULL ? "<ERROR>" : fp);
+		r = SSH_ERR_INVALID_FORMAT;
 		goto done;
 	}
 	ident = format_identity(id);
diff --git a/sshsig.c b/sshsig.c
index 6e03c0b0..3da005d6 100644
--- a/sshsig.c
+++ b/sshsig.c
@@ -879,6 +879,7 @@ cert_filter_principals(const char *path, u_long linenum,
 	}
 	if ((principals = sshbuf_dup_string(nprincipals)) == NULL) {
 		error_f("buffer error");
+		r = SSH_ERR_ALLOC_FAIL;
 		goto out;
 	}
 	/* success */