diff --git a/sys/cam/ctl/ctl.c b/sys/cam/ctl/ctl.c
index 084645ec7e3f..d21bd5abefee 100644
--- a/sys/cam/ctl/ctl.c
+++ b/sys/cam/ctl/ctl.c
@@ -11091,6 +11091,8 @@ ctl_check_for_blockage(struct ctl_lun *lun, union ctl_io *pending_io,
 	     __func__, pending_entry->seridx, pending_io->scsiio.cdb[0],
 	     pending_io->scsiio.cdb[1], pending_io));
 	ooa_entry = ctl_get_cmd_entry(&ooa_io->scsiio, NULL);
+	if (ooa_entry->seridx == CTL_SERIDX_INVLD)
+		return (CTL_ACTION_PASS); /* Unsupported command in OOA queue */
 	KASSERT(ooa_entry->seridx < CTL_SERIDX_COUNT,
 	    ("%s: Invalid seridx %d for ooa CDB %02x %02x @ %p",
 	     __func__, ooa_entry->seridx, ooa_io->scsiio.cdb[0],