diff --git a/sys/netpfil/pf/pf.c b/sys/netpfil/pf/pf.c
--- a/sys/netpfil/pf/pf.c
+++ b/sys/netpfil/pf/pf.c
@@ -8415,6 +8415,12 @@
 	if (m->m_flags & M_SKIP_FIREWALL)
 		return (PF_PASS);
 
+	if (__predict_false(! M_WRITABLE(*m0))) {
+		m = *m0 = m_unshare(*m0, M_NOWAIT);
+		if (*m0 == NULL)
+			return (PF_DROP);
+	}
+
 	/* Stateless! */
 	return (pf_test_eth_rule(dir, kif, m0));
 }
@@ -8553,6 +8559,12 @@
 		return (PF_PASS);
 	}
 
+	if (__predict_false(! M_WRITABLE(*m0))) {
+		m = *m0 = m_unshare(*m0, M_NOWAIT);
+		if (*m0 == NULL)
+			return (PF_DROP);
+	}
+
 	memset(&pd, 0, sizeof(pd));
 	TAILQ_INIT(&pd.sctp_multihome_jobs);
 	if (default_actions != NULL)
@@ -9147,6 +9159,12 @@
 		return (PF_DROP);
 	}
 
+	if (__predict_false(! M_WRITABLE(*m0))) {
+		m = *m0 = m_unshare(*m0, M_NOWAIT);
+		if (*m0 == NULL)
+			return (PF_DROP);
+	}
+
 	memset(&pd, 0, sizeof(pd));
 	TAILQ_INIT(&pd.sctp_multihome_jobs);
 	if (default_actions != NULL)