ror = EINVAL;
+			goto fail;
+		}
+		if (strnlen(io->pfrio_table.pfrt_name, PF_TABLE_NAME_SIZE)
+		    == PF_TABLE_NAME_SIZE) {
+			error = EINVAL;
+			goto fail;
+		}
+
 		PF_RULES_WLOCK();
 		error = pfr_clr_tables(&io->pfrio_table, &io->pfrio_ndel,
 		    io->pfrio_flags | PFR_FLAG_USERIOCTL);
diff --git a/tests/sys/netpfil/pf/ioctl/validation.c b/tests/sys/netpfil/pf/ioctl/validation.c
index ff3f1bbcdadc..7a1d2b3800cd 100644
--- a/tests/sys/netpfil/pf/ioctl/validation.c
+++ b/tests/sys/netpfil/pf/ioctl/validation.c
@@ -193,6 +193,38 @@ ATF_TC_CLEANUP(gettables, tc)
 	COMMON_CLEANUP();
 }
 
+ATF_TC_WITH_CLEANUP(clrtables);
+ATF_TC_HEAD(clrtables, tc)
+{
+	atf_tc_set_md_var(tc, "require.user", "root");
+	atf_tc_set_md_var(tc, "require.kmods", "pf");
+}
+
+ATF_TC_BODY(clrtables, tc)
+{
+	struct pfioc_table io;
+	struct pfr_table tbl;
+	int flags;
+
+	COMMON_HEAD();
+
+	flags = 0;
+
+	memset(&io, '/', sizeof(io));
+	io.pfrio_flags = flags;
+	io.pfrio_buffer = &tbl;
+	io.pfrio_esize = 0;
+	io.pfrio_size = 1;
+
+	if (ioctl(dev, DIOCRCLRTABLES, &io) == 0)
+		atf_tc_fail("Request with unterminated anchor name succeeded");
+}
+
+ATF_TC_CLEANUP(clrtables, tc)
+{
+	COMMON_CLEANUP();
+}
+
 ATF_TC_WITH_CLEANUP(gettstats);
 ATF_TC_HEAD(gettstats, tc)
 {
@@ -957,6 +989,7 @@ ATF_TP_ADD_TCS(tp)
 	ATF_TP_ADD_TC(tp, addtables);
 	ATF_TP_ADD_TC(tp, deltables);
 	ATF_TP_ADD_TC(tp, gettables);
+	ATF_TP_ADD_TC(tp, clrtables);
 	ATF_TP_ADD_TC(tp, getastats);
 	ATF_TP_ADD_TC(tp, gettstats);
 	ATF_TP_ADD_TC(tp, clrtstats);