diff --git a/sys/netpfil/pf/pf_ioctl.c b/sys/netpfil/pf/pf_ioctl.c
--- a/sys/netpfil/pf/pf_ioctl.c
+++ b/sys/netpfil/pf/pf_ioctl.c
@@ -5584,6 +5584,8 @@
 			break;
 		}
 
+		io->pfiio_name[sizeof(io->pfiio_name) - 1] = '\0';
+
 		bufsiz = io->pfiio_size * sizeof(struct pfi_kif);
 		ifstore = mallocarray(io->pfiio_size, sizeof(struct pfi_kif),
 		    M_TEMP, M_WAITOK | M_ZERO);
@@ -5599,6 +5601,8 @@
 	case DIOCSETIFFLAG: {
 		struct pfioc_iface *io = (struct pfioc_iface *)addr;
 
+		io->pfiio_name[sizeof(io->pfiio_name) - 1] = '\0';
+
 		PF_RULES_WLOCK();
 		error = pfi_set_flags(io->pfiio_name, io->pfiio_flags);
 		PF_RULES_WUNLOCK();
@@ -5608,6 +5612,8 @@
 	case DIOCCLRIFFLAG: {
 		struct pfioc_iface *io = (struct pfioc_iface *)addr;
 
+		io->pfiio_name[sizeof(io->pfiio_name) - 1] = '\0';
+
 		PF_RULES_WLOCK();
 		error = pfi_clear_flags(io->pfiio_name, io->pfiio_flags);
 		PF_RULES_WUNLOCK();