diff --git a/apps/dav/lib/CalDAV/CalDavBackend.php b/apps/dav/lib/CalDAV/CalDavBackend.php
index e49e47879b0e5..e335867a7da75 100644
--- a/apps/dav/lib/CalDAV/CalDavBackend.php
+++ b/apps/dav/lib/CalDAV/CalDavBackend.php
@@ -215,6 +215,7 @@ class CalDavBackend extends AbstractBackend implements SyncSupport, Subscription
 	private IConfig $config;
 	private bool $legacyEndpoint;
 	private string $dbObjectPropertiesTable = 'calendarobjects_props';
+	private array $cachedObjects = [];
 
 	public function __construct(IDBConnection $db,
 								Principal $principalBackend,
@@ -1117,6 +1118,10 @@ public function getDeletedCalendarObjectsByPrincipal(string $principalUri): arra
 	 * @return array|null
 	 */
 	public function getCalendarObject($calendarId, $objectUri, int $calendarType = self::CALENDAR_TYPE_CALENDAR) {
+		$key = $calendarId . '::' . $objectUri . '::' . $calendarType;
+		if (isset($this->cachedObjects[$key])) {
+			return $this->cachedObjects[$key];
+		}
 		$query = $this->db->getQueryBuilder();
 		$query->select(['id', 'uri', 'lastmodified', 'etag', 'calendarid', 'size', 'calendardata', 'componenttype', 'classification', 'deleted_at'])
 			->from('calendarobjects')
@@ -1131,6 +1136,12 @@ public function getCalendarObject($calendarId, $objectUri, int $calendarType = s
 			return null;
 		}
 
+		$object = $this->rowToCalendarObject($row);
+		$this->cachedObjects[$key] = $object;
+		return $object;
+	}
+
+	private function rowToCalendarObject(array $row): array {
 		return [
 			'id' => $row['id'],
 			'uri' => $row['uri'],
@@ -1217,6 +1228,7 @@ public function getMultipleCalendarObjects($calendarId, array $uris, $calendarTy
 	 * @return string
 	 */
 	public function createCalendarObject($calendarId, $objectUri, $calendarData, $calendarType = self::CALENDAR_TYPE_CALENDAR) {
+		$this->cachedObjects = [];
 		$extraData = $this->getDenormalizedData($calendarData);
 
 		// Try to detect duplicates
@@ -1309,6 +1321,7 @@ public function createCalendarObject($calendarId, $objectUri, $calendarData, $ca
 	 * @return string
 	 */
 	public function updateCalendarObject($calendarId, $objectUri, $calendarData, $calendarType = self::CALENDAR_TYPE_CALENDAR) {
+		$this->cachedObjects = [];
 		$extraData = $this->getDenormalizedData($calendarData);
 		$query = $this->db->getQueryBuilder();
 		$query->update('calendarobjects')
@@ -1359,6 +1372,7 @@ public function updateCalendarObject($calendarId, $objectUri, $calendarData, $ca
 	 * @throws Exception
 	 */
 	public function moveCalendarObject(int $sourceCalendarId, int $targetCalendarId, int $objectId, string $oldPrincipalUri, string $newPrincipalUri, int $calendarType = self::CALENDAR_TYPE_CALENDAR): bool {
+		$this->cachedObjects = [];
 		$object = $this->getCalendarObjectById($oldPrincipalUri, $objectId);
 		if (empty($object)) {
 			return false;
@@ -1404,6 +1418,7 @@ public function moveCalendarObject(int $sourceCalendarId, int $targetCalendarId,
 	 * @param int $classification
 	 */
 	public function setClassification($calendarObjectId, $classification) {
+		$this->cachedObjects = [];
 		if (!in_array($classification, [
 			self::CLASSIFICATION_PUBLIC, self::CLASSIFICATION_PRIVATE, self::CLASSIFICATION_CONFIDENTIAL
 		])) {
@@ -1428,6 +1443,7 @@ public function setClassification($calendarObjectId, $classification) {
 	 * @return void
 	 */
 	public function deleteCalendarObject($calendarId, $objectUri, $calendarType = self::CALENDAR_TYPE_CALENDAR, bool $forceDeletePermanently = false) {
+		$this->cachedObjects = [];
 		$data = $this->getCalendarObject($calendarId, $objectUri, $calendarType);
 
 		if ($data === null) {
@@ -1507,6 +1523,7 @@ public function deleteCalendarObject($calendarId, $objectUri, $calendarType = se
 	 * @throws Forbidden
 	 */
 	public function restoreCalendarObject(array $objectData): void {
+		$this->cachedObjects = [];
 		$id = (int) $objectData['id'];
 		$restoreUri = str_replace("-deleted.ics", ".ics", $objectData['uri']);
 		$targetObject = $this->getCalendarObject(
@@ -1632,12 +1649,8 @@ public function calendarQuery($calendarId, array $filters, $calendarType = self:
 				}
 			}
 		}
-		$columns = ['uri'];
-		if ($requirePostFilter) {
-			$columns = ['uri', 'calendardata'];
-		}
 		$query = $this->db->getQueryBuilder();
-		$query->select($columns)
+		$query->select(['id', 'uri', 'lastmodified', 'etag', 'calendarid', 'size', 'calendardata', 'componenttype', 'classification', 'deleted_at'])
 			->from('calendarobjects')
 			->where($query->expr()->eq('calendarid', $query->createNamedParameter($calendarId)))
 			->andWhere($query->expr()->eq('calendartype', $query->createNamedParameter($calendarType)))
@@ -1658,6 +1671,11 @@ public function calendarQuery($calendarId, array $filters, $calendarType = self:
 
 		$result = [];
 		while ($row = $stmt->fetch()) {
+			// if we leave it as a blob we can't read it both from the post filter and the rowToCalendarObject
+			if (isset($row['calendardata'])) {
+				$row['calendardata'] = $this->readBlob($row['calendardata']);
+			}
+
 			if ($requirePostFilter) {
 				// validateFilterForObject will parse the calendar data
 				// catch parsing errors
@@ -1682,6 +1700,8 @@ public function calendarQuery($calendarId, array $filters, $calendarType = self:
 				}
 			}
 			$result[] = $row['uri'];
+			$key = $calendarId . '::' . $row['uri'] . '::' . $calendarType;
+			$this->cachedObjects[$key] = $this->rowToCalendarObject($row);
 		}
 
 		return $result;
@@ -2631,6 +2651,7 @@ public function getSchedulingObjects($principalUri) {
 	 * @return void
 	 */
 	public function deleteSchedulingObject($principalUri, $objectUri) {
+		$this->cachedObjects = [];
 		$query = $this->db->getQueryBuilder();
 		$query->delete('schedulingobjects')
 				->where($query->expr()->eq('principaluri', $query->createNamedParameter($principalUri)))
@@ -2647,6 +2668,7 @@ public function deleteSchedulingObject($principalUri, $objectUri) {
 	 * @return void
 	 */
 	public function createSchedulingObject($principalUri, $objectUri, $objectData) {
+		$this->cachedObjects = [];
 		$query = $this->db->getQueryBuilder();
 		$query->insert('schedulingobjects')
 			->values([
@@ -2670,6 +2692,7 @@ public function createSchedulingObject($principalUri, $objectUri, $objectData) {
 	 * @return void
 	 */
 	protected function addChange($calendarId, $objectUri, $operation, $calendarType = self::CALENDAR_TYPE_CALENDAR) {
+		$this->cachedObjects = [];
 		$table = $calendarType === self::CALENDAR_TYPE_CALENDAR ? 'calendars': 'calendarsubscriptions';
 
 		$query = $this->db->getQueryBuilder();
@@ -2836,6 +2859,10 @@ public function getShares(int $resourceId): array {
 		return $this->calendarSharingBackend->getShares($resourceId);
 	}
 
+	public function preloadShares(array $resourceIds): void {
+		$this->calendarSharingBackend->preloadShares($resourceIds);
+	}
+
 	/**
 	 * @param boolean $value
 	 * @param \OCA\DAV\CalDAV\Calendar $calendar
@@ -2905,6 +2932,7 @@ public function applyShareAcl(int $resourceId, array $acl): array {
 	 * @param int $calendarType
 	 */
 	public function updateProperties($calendarId, $objectUri, $calendarData, $calendarType = self::CALENDAR_TYPE_CALENDAR) {
+		$this->cachedObjects = [];
 		$objectId = $this->getCalendarObjectId($calendarId, $objectUri, $calendarType);
 
 		try {
@@ -3063,6 +3091,7 @@ protected function readCalendarData($objectData) {
 	 * @param int $objectId
 	 */
 	protected function purgeProperties($calendarId, $objectId) {
+		$this->cachedObjects = [];
 		$query = $this->db->getQueryBuilder();
 		$query->delete($this->dbObjectPropertiesTable)
 			->where($query->expr()->eq('objectid', $query->createNamedParameter($objectId)))
diff --git a/apps/dav/lib/CalDAV/CalendarHome.php b/apps/dav/lib/CalDAV/CalendarHome.php
index cd6ae1c2f7fd7..af25f6c454666 100644
--- a/apps/dav/lib/CalDAV/CalendarHome.php
+++ b/apps/dav/lib/CalDAV/CalendarHome.php
@@ -58,6 +58,7 @@ class CalendarHome extends \Sabre\CalDAV\CalendarHome {
 
 	/** @var LoggerInterface */
 	private $logger;
+	private ?array $cachedChildren = null;
 
 	public function __construct(BackendInterface $caldavBackend, $principalInfo, LoggerInterface $logger) {
 		parent::__construct($caldavBackend, $principalInfo);
@@ -97,6 +98,9 @@ public function createExtendedCollection($name, MkCol $mkCol): void {
 	 * @inheritdoc
 	 */
 	public function getChildren() {
+		if ($this->cachedChildren) {
+			return $this->cachedChildren;
+		}
 		$calendars = $this->caldavBackend->getCalendarsForUser($this->principalInfo['uri']);
 		$objects = [];
 		foreach ($calendars as $calendar) {
@@ -136,6 +140,7 @@ public function getChildren() {
 			}
 		}
 
+		$this->cachedChildren = $objects;
 		return $objects;
 	}
 
diff --git a/apps/dav/lib/DAV/Sharing/Backend.php b/apps/dav/lib/DAV/Sharing/Backend.php
index 90d2c7ebf82fd..4e17f2867678e 100644
--- a/apps/dav/lib/DAV/Sharing/Backend.php
+++ b/apps/dav/lib/DAV/Sharing/Backend.php
@@ -29,6 +29,7 @@
 namespace OCA\DAV\DAV\Sharing;
 
 use OCA\DAV\Connector\Sabre\Principal;
+use OCP\Cache\CappedMemoryCache;
 use OCP\IDBConnection;
 use OCP\IGroupManager;
 use OCP\IUserManager;
@@ -45,12 +46,15 @@ class Backend {
 	public const ACCESS_READ_WRITE = 2;
 	public const ACCESS_READ = 3;
 
+	private CappedMemoryCache $shareCache;
+
 	public function __construct(IDBConnection $db, IUserManager $userManager, IGroupManager $groupManager, Principal $principalBackend, string $resourceType) {
 		$this->db = $db;
 		$this->userManager = $userManager;
 		$this->groupManager = $groupManager;
 		$this->principalBackend = $principalBackend;
 		$this->resourceType = $resourceType;
+		$this->shareCache = new CappedMemoryCache();
 	}
 
 	/**
@@ -58,6 +62,7 @@ public function __construct(IDBConnection $db, IUserManager $userManager, IGroup
 	 * @param list<string> $remove
 	 */
 	public function updateShares(IShareable $shareable, array $add, array $remove): void {
+		$this->shareCache->clear();
 		foreach ($add as $element) {
 			$principal = $this->principalBackend->findByUri($element['href'], '');
 			if ($principal !== '') {
@@ -76,6 +81,7 @@ public function updateShares(IShareable $shareable, array $add, array $remove):
 	 * @param array{href: string, commonName: string, readOnly: bool} $element
 	 */
 	private function shareWith(IShareable $shareable, array $element): void {
+		$this->shareCache->clear();
 		$user = $element['href'];
 		$parts = explode(':', $user, 2);
 		if ($parts[0] !== 'principal') {
@@ -119,6 +125,7 @@ private function shareWith(IShareable $shareable, array $element): void {
 	}
 
 	public function deleteAllShares(int $resourceId): void {
+		$this->shareCache->clear();
 		$query = $this->db->getQueryBuilder();
 		$query->delete('dav_shares')
 			->where($query->expr()->eq('resourceid', $query->createNamedParameter($resourceId)))
@@ -127,6 +134,7 @@ public function deleteAllShares(int $resourceId): void {
 	}
 
 	public function deleteAllSharesByUser(string $principaluri): void {
+		$this->shareCache->clear();
 		$query = $this->db->getQueryBuilder();
 		$query->delete('dav_shares')
 			->where($query->expr()->eq('principaluri', $query->createNamedParameter($principaluri)))
@@ -135,6 +143,7 @@ public function deleteAllSharesByUser(string $principaluri): void {
 	}
 
 	private function unshare(IShareable $shareable, string $element): void {
+		$this->shareCache->clear();
 		$parts = explode(':', $element, 2);
 		if ($parts[0] !== 'principal') {
 			return;
@@ -167,6 +176,10 @@ private function unshare(IShareable $shareable, string $element): void {
 	 * @return list<array{href: string, commonName: string, status: int, readOnly: bool, '{http://owncloud.org/ns}principal': string, '{http://owncloud.org/ns}group-share': bool}>
 	 */
 	public function getShares(int $resourceId): array {
+		$cached = $this->shareCache->get($resourceId);
+		if ($cached) {
+			return $cached;
+		}
 		$query = $this->db->getQueryBuilder();
 		$result = $query->select(['principaluri', 'access'])
 			->from('dav_shares')
@@ -188,9 +201,44 @@ public function getShares(int $resourceId): array {
 			];
 		}
 
+		$this->shareCache->set((string) $resourceId, $shares);
 		return $shares;
 	}
 
+	public function preloadShares(array $resourceIds): void {
+		$resourceIds = array_filter($resourceIds, function(int $resourceId) {
+			return !isset($this->shareCache[(string) $resourceId]);
+		});
+		if (count($resourceIds) === 0) {
+			return;
+		}
+		$query = $this->db->getQueryBuilder();
+		$result = $query->select(['resourceid', 'principaluri', 'access'])
+			->from('dav_shares')
+			->where($query->expr()->in('resourceid', $query->createNamedParameter($resourceIds, IQueryBuilder::PARAM_INT_ARRAY)))
+			->andWhere($query->expr()->eq('type', $query->createNamedParameter($this->resourceType)))
+			->groupBy(['principaluri', 'access', 'resourceid'])
+			->executeQuery();
+
+		$sharesByResource = array_fill_keys($resourceIds, []);
+		while ($row = $result->fetch()) {
+			$resourceId = (int)$row['resourceid'];
+			$p = $this->principalBackend->getPrincipalByPath($row['principaluri']);
+			$sharesByResource[$resourceId][] = [
+				'href' => "principal:{$row['principaluri']}",
+				'commonName' => isset($p['{DAV:}displayname']) ? (string)$p['{DAV:}displayname'] : '',
+				'status' => 1,
+				'readOnly' => (int) $row['access'] === self::ACCESS_READ,
+				'{http://owncloud.org/ns}principal' => (string)$row['principaluri'],
+				'{http://owncloud.org/ns}group-share' => isset($p['uri']) ? str_starts_with($p['uri'], 'principals/groups') : false
+			];
+		}
+
+		foreach ($resourceIds as $resourceId) {
+			$this->shareCache->set((string) $resourceId, $sharesByResource[$resourceId]);
+		}
+	}
+
 	/**
 	 * For shared resources the sharee is set in the ACL of the resource
 	 *
diff --git a/apps/dav/lib/DAV/Sharing/Plugin.php b/apps/dav/lib/DAV/Sharing/Plugin.php
index a4b2cd3681cc7..8ddcb664fd51f 100644
--- a/apps/dav/lib/DAV/Sharing/Plugin.php
+++ b/apps/dav/lib/DAV/Sharing/Plugin.php
@@ -24,6 +24,8 @@
  */
 namespace OCA\DAV\DAV\Sharing;
 
+use OCA\DAV\CalDAV\CalDavBackend;
+use OCA\DAV\CalDAV\CalendarHome;
 use OCA\DAV\Connector\Sabre\Auth;
 use OCA\DAV\DAV\Sharing\Xml\Invite;
 use OCA\DAV\DAV\Sharing\Xml\ShareRequest;
@@ -201,6 +203,20 @@ public function httpPost(RequestInterface $request, ResponseInterface $response)
 	 * @return void
 	 */
 	public function propFind(PropFind $propFind, INode $node) {
+		if ($node instanceof CalendarHome && $propFind->getDepth() === 1) {
+			$backend = $node->getCalDAVBackend();
+			if ($backend instanceof CalDavBackend) {
+				$calendars = $node->getChildren();
+				$calendars = array_filter($calendars, function (INode $node) {
+					return $node instanceof IShareable;
+				});
+				/** @var int[] $resourceIds */
+				$resourceIds = array_map(function (IShareable $node) {
+					return $node->getResourceId();
+				}, $calendars);
+				$backend->preloadShares($resourceIds);
+			}
+		}
 		if ($node instanceof IShareable) {
 			$propFind->handle('{' . Plugin::NS_OWNCLOUD . '}invite', function () use ($node) {
 				return new Invite(