diff --git a/radicale/item/__init__.py b/radicale/item/__init__.py
index 26c93849..975e4e7a 100644
--- a/radicale/item/__init__.py
+++ b/radicale/item/__init__.py
@@ -247,51 +247,51 @@ def check_and_sanitize_items(
             if hasattr(component, "rrule"):
                 # workaround for vobject < 1.0.0 as it has no limiter in "getrruleset"
                 logger.trace("Recurrence rule found in %s in object %r: %r", component.name, component_uid, component.rrule.value)
-                # early check of maximum of COUNT to avoid DoS (semi-ugly workaround)
-                pattern = re.compile('.*;COUNT=(\\d+)(;.*)?$')
-                match = pattern.match(component.rrule.value)
-                if match:
-                    rrule_count = int(match[1])
-                    if max_vevent_rrule_occurrence > 0 and rrule_count > max_vevent_rrule_occurrence:
-                        logger.error("Recurrence rule %r count in %s in object %r: %d (REJECTED/limit: %d)", component.rrule.value, component.name, component_uid, rrule_count, max_vevent_rrule_occurrence)
+                if not hasattr(component, "dtstart"):
+                    # e.g. VTODO
+                    rrule = vobject.icalendar.rrule.rrulestr(component.rrule.value)
+                else:
+                    dtstart = radicale_filter.date_to_datetime(component.dtstart.value)
+                    ignoretz = (
+                        not isinstance(dtstart, datetime.datetime)
+                        or dtstart.tzinfo is None
+                    )
+                    rrule = vobject.icalendar.rrule.rrulestr(component.rrule.value, ignoretz=ignoretz)
+                # early check of maximum of COUNT to avoid DoS (workaround)
+                if hasattr(rrule, "_count") and rrule._count is not None:
+                    logger.trace("Recurrence rule %r in %s in object %r contains: COUNT=%d", component.rrule.value, component.name, component_uid, rrule._count)
+                    if max_vevent_rrule_occurrence > 0 and rrule._count > max_vevent_rrule_occurrence:
+                        logger.error("Recurrence rule %r count in %s in object %r: %d (REJECTED/limit: %d)", component.rrule.value, component.name, component_uid, rrule._count, max_vevent_rrule_occurrence)
                         raise ValueError("Too many recurrence rule entries in %s in object %r: %d (limit: %d)"
-                                         % (component.name, component_uid, rrule_count, max_vevent_rrule_occurrence))
+                                         % (component.name, component_uid, rrule._count, max_vevent_rrule_occurrence))
                     else:
-                        logger.debug("Recurrence rule count in %s in object %r: %d (PASSED/limit: %d)" % (component.name, component_uid, rrule_count, max_vevent_rrule_occurrence))
-                if hasattr(component, "dtstart"):
-                    # early check of maximum of (UNTIL-DTSTART)/interval(FREQ) to avoid DoS (ugly workaround with some guessing)
-                    pattern = re.compile('FREQ=([A-Z]+)(;.*)?$')
-                    match = pattern.match(component.rrule.value)
-                    if match and match[1] in RRULE_FREQUENCIES_TO_INTERVAL:
-                        # RRULE has known FREQ
-                        freq = match[1]
-                        pattern = re.compile('.*;UNTIL=([\\dTZ]+)(;.*)?$')
-                        match = pattern.match(component.rrule.value)
-                        dtstart = radicale_filter.date_to_datetime(component.dtstart.value)
-                        if match:
-                            # RRULE has UNTIL
-                            ignoretz = (
-                                not isinstance(dtstart, datetime.datetime)
-                                or dtstart.tzinfo is None
-                            )
-                            until = vobject.icalendar.rrule.rrulestr(component.rrule.value, ignoretz=ignoretz)._until
-                            if dtstart.tzinfo is not None:
-                                until = until.astimezone(dtstart.tzinfo)
-                            delta = until - dtstart
-                            seconds = delta.total_seconds()
-                            if seconds < 0:
-                                # UNTIL < DTSTART
-                                logger.error("Recurrence rule %r in %s in object %r REJECTED, UNTIL < DTSTART", component.rrule.value, component.name, component_uid)
-                                raise ValueError("Recurrence rule in %s in object %r has UNTIL < DTSTART"
-                                                 % (component.name, component_uid))
-                            rrule_entries = seconds / RRULE_FREQUENCIES_TO_INTERVAL[freq]
-                            logger.trace("estimated rule entries: %d", rrule_entries)
-                            if max_vevent_rrule_occurrence > 0 and rrule_entries > max_vevent_rrule_occurrence:
-                                logger.warning("Recurrence rule %r entries in %s in object %r: %d (estimated/REJECTED/limit: %d)", component.rrule.value, component.name, component_uid, rrule_entries, max_vevent_rrule_occurrence)
-                                raise ValueError("Too many recurrence rule entries in %s in object %r: %d (limit: %d)"
-                                                 % (component.name, component_uid, rrule_entries, max_vevent_rrule_occurrence))
-                            else:
-                                logger.debug("Recurrence rule %r entries in %s in object %r: %d (estimated/PASSED/limit: %d)" % (component.rrule.value, component.name, component_uid, rrule_entries, max_vevent_rrule_occurrence))
+                        logger.debug("Recurrence rule count in %s in object %r: %d (PASSED/limit: %d)" % (component.name, component_uid, rrule._count, max_vevent_rrule_occurrence))
+                else:
+                    logger.trace("Recurrence rule %r in %s in object %r doesn't contain: COUNT", component.rrule.value, component.name, component_uid)
+                # early check of maximum of (UNTIL-DTSTART)/interval(FREQ) to avoid DoS (ugly workaround with some guessing)
+                if hasattr(rrule, "_freq") and rrule._freq is not None and hasattr(rrule, "_until") and rrule._until is not None and hasattr(component, "dtstart"):
+                    if vobject.icalendar.FREQUENCIES[rrule._freq] not in RRULE_FREQUENCIES_TO_INTERVAL:
+                        raise ValueError("Unsupported FREQ in recurrence rule in %s in object %r: %r"
+                                         % (component.name, component_uid, rrule._freq))
+                    # RRULE has known FREQ+UNTIL+DTSTART
+                    if dtstart.tzinfo is not None:
+                        rrule._until = rrule._until.astimezone(dtstart.tzinfo)
+                    delta = rrule._until - dtstart
+                    seconds = delta.total_seconds()
+                    if seconds < 0:
+                        # UNTIL < DTSTART
+                        logger.error("Recurrence rule %r in %s in object %r REJECTED, UNTIL < DTSTART", component.rrule.value, component.name, component_uid)
+                        raise ValueError("Recurrence rule in %s in object %r has UNTIL < DTSTART"
+                                         % (component.name, component_uid))
+                    rrule_entries = seconds / RRULE_FREQUENCIES_TO_INTERVAL[vobject.icalendar.FREQUENCIES[rrule._freq]]
+                    if max_vevent_rrule_occurrence > 0 and rrule_entries > max_vevent_rrule_occurrence:
+                        logger.warning("Recurrence rule %r entries in %s in object %r: %d (estimated/REJECTED/limit: %d)", component.rrule.value, component.name, component_uid, rrule_entries, max_vevent_rrule_occurrence)
+                        raise ValueError("Too many recurrence rule entries in %s in object %r: %d (limit: %d)"
+                                         % (component.name, component_uid, rrule_entries, max_vevent_rrule_occurrence))
+                    else:
+                        logger.debug("Recurrence rule %r entries in %s in object %r: %d (estimated/PASSED/limit: %d)" % (component.rrule.value, component.name, component_uid, rrule_entries, max_vevent_rrule_occurrence))
+                else:
+                    logger.trace("Recurrence rule %r in %s in object %r doesn't contain: FREQ+UNTIL", component.rrule.value, component.name, component_uid)
                 # generic check by vobject
                 try:
                     rruleset = component.rruleset