diff --git a/sys/net/pfvar.h b/sys/net/pfvar.h
index 70fde0aa738..1dfc769b197 100644
--- a/sys/net/pfvar.h
+++ b/sys/net/pfvar.h
@@ -1852,6 +1852,7 @@ void		 pf_send_tcp(const struct pf_krule *, sa_family_t,
 			    u_int16_t);
 
 void			 pf_syncookies_init(void);
+void			 pf_syncookies_cleanup(void);
 int			 pf_get_syncookies(struct pfioc_nv *);
 int			 pf_set_syncookies(struct pfioc_nv *);
 int			 pf_synflood_check(struct pf_pdesc *);
diff --git a/sys/netpfil/pf/pf_ioctl.c b/sys/netpfil/pf/pf_ioctl.c
index a9f5b2c1804..27e1a145f3e 100644
--- a/sys/netpfil/pf/pf_ioctl.c
+++ b/sys/netpfil/pf/pf_ioctl.c
@@ -5573,6 +5573,7 @@ pf_unload_vnet(void)
 	dehook_pf();
 
 	PF_RULES_WLOCK();
+	pf_syncookies_cleanup();
 	shutdown_pf();
 	PF_RULES_WUNLOCK();
 
diff --git a/sys/netpfil/pf/pf_syncookies.c b/sys/netpfil/pf/pf_syncookies.c
index 0313b817ad6..8699ae855ec 100644
--- a/sys/netpfil/pf/pf_syncookies.c
+++ b/sys/netpfil/pf/pf_syncookies.c
@@ -127,6 +127,12 @@ pf_syncookies_init(void)
 	PF_RULES_WUNLOCK();
 }
 
+void
+pf_syncookies_cleanup(void)
+{
+	callout_stop(&V_pf_syncookie_status.keytimeout);
+}
+
 int
 pf_get_syncookies(struct pfioc_nv *nv)
 {