diff --git a/lib/Cron/DeleteCron.php b/lib/Cron/DeleteCron.php
index 97854181f..6b762881c 100644
--- a/lib/Cron/DeleteCron.php
+++ b/lib/Cron/DeleteCron.php
@@ -13,6 +13,7 @@ use OCA\Deck\Db\CardMapper;
 use OCA\Deck\Db\StackMapper;
 use OCA\Deck\InvalidAttachmentType;
 use OCA\Deck\Service\AttachmentService;
+use OCA\Deck\Sharing\DeckShareProvider;
 use OCP\AppFramework\Utility\ITimeFactory;
 use OCP\BackgroundJob\IJob;
 use OCP\BackgroundJob\TimedJob;
@@ -29,14 +30,25 @@ class DeleteCron extends TimedJob {
 	private $attachmentMapper;
 	/** @var StackMapper */
 	private $stackMapper;
+	/** @var DeckShareProvider */
+	private $deckShareProvider;
 
-	public function __construct(ITimeFactory $time, BoardMapper $boardMapper, CardMapper $cardMapper, AttachmentService $attachmentService, AttachmentMapper $attachmentMapper, StackMapper $stackMapper) {
+	public function __construct(
+		ITimeFactory $time,
+		BoardMapper $boardMapper,
+		CardMapper $cardMapper,
+		AttachmentService $attachmentService,
+		AttachmentMapper $attachmentMapper,
+		StackMapper $stackMapper,
+		DeckShareProvider $deckShareProvider,
+	) {
 		parent::__construct($time);
 		$this->boardMapper = $boardMapper;
 		$this->cardMapper = $cardMapper;
 		$this->attachmentService = $attachmentService;
 		$this->attachmentMapper = $attachmentMapper;
 		$this->stackMapper = $stackMapper;
+		$this->deckShareProvider = $deckShareProvider;
 
 		$this->setInterval(60 * 60 * 24);
 		$this->setTimeSensitivity(IJob::TIME_INSENSITIVE);
@@ -69,6 +81,12 @@ class DeleteCron extends TimedJob {
 			$this->attachmentMapper->delete($attachment);
 		}
 
+		// Delete orphaned attachment shares
+		$shares = $this->deckShareProvider->getOrphanedAttachmentShares();
+		foreach ($shares as $share) {
+			$this->deckShareProvider->delete($share);
+		}
+
 		$stacks = $this->stackMapper->findToDelete();
 		foreach ($stacks as $stack) {
 			$this->stackMapper->delete($stack);
diff --git a/lib/Db/CardMapper.php b/lib/Db/CardMapper.php
index 64a0f5a1b..abec4e0ca 100644
--- a/lib/Db/CardMapper.php
+++ b/lib/Db/CardMapper.php
@@ -644,4 +644,16 @@ class CardMapper extends QBMapper implements IPermissionMapper {
 
 		$result->closeCursor();
 	}
+
+	public function getAllCardIds(): array {
+		$qb = $this->db->getQueryBuilder();
+		$qb->select('id')
+			->from('deck_cards');
+		$result = $qb->executeQuery();
+		$ids = [];
+		while ($row = $result->fetch()) {
+			$ids[] = (int)$row['id'];
+		}
+		return $ids;
+	}
 }
diff --git a/lib/Sharing/DeckShareProvider.php b/lib/Sharing/DeckShareProvider.php
index be5eb88af..8b39646aa 100644
--- a/lib/Sharing/DeckShareProvider.php
+++ b/lib/Sharing/DeckShareProvider.php
@@ -1045,4 +1045,21 @@ class DeckShareProvider implements \OCP\Share\IShareProvider {
 		}
 		$cursor->closeCursor();
 	}
+
+	public function getOrphanedAttachmentShares(): array {
+		$allCardIds = $this->cardMapper->getAllCardIds();
+		$qb = $this->dbConnection->getQueryBuilder();
+		$qb->select('*')
+			->from('share', 's')
+			->where($qb->expr()->eq('s.share_type', $qb->createNamedParameter(IShare::TYPE_DECK)))
+			->andWhere($qb->expr()->notIn('s.share_with', $qb->createNamedParameter($allCardIds, IQueryBuilder::PARAM_STR_ARRAY)));
+
+		$cursor = $qb->execute();
+		$shares = [];
+		while ($data = $cursor->fetch()) {
+			$shares[] = $this->createShareObject($data);
+		}
+
+		return $shares;
+	}
 }
diff --git a/tests/unit/Cron/DeleteCronTest.php b/tests/unit/Cron/DeleteCronTest.php
index 1ed5f4472..751145023 100644
--- a/tests/unit/Cron/DeleteCronTest.php
+++ b/tests/unit/Cron/DeleteCronTest.php
@@ -34,6 +34,7 @@ use OCA\Deck\Db\StackMapper;
 use OCA\Deck\InvalidAttachmentType;
 use OCA\Deck\Service\AttachmentService;
 use OCA\Deck\Service\IAttachmentService;
+use OCA\Deck\Sharing\DeckShareProvider;
 use OCP\AppFramework\Utility\ITimeFactory;
 use PHPUnit\Framework\MockObject\MockObject;
 use Test\TestCase;
@@ -52,6 +53,8 @@ class DeleteCronTest extends TestCase {
 	private $attachmentMapper;
 	/** @var StackMapper|MockObject */
 	private $stackMapper;
+	/** @var DeckShareProvider */
+	private $deckShareProvider;
 	/** @var DeleteCron */
 	protected $deleteCron;
 
@@ -63,7 +66,16 @@ class DeleteCronTest extends TestCase {
 		$this->attachmentService = $this->createMock(AttachmentService::class);
 		$this->attachmentMapper = $this->createMock(AttachmentMapper::class);
 		$this->stackMapper = $this->createMock(StackMapper::class);
-		$this->deleteCron = new DeleteCron($this->timeFactory, $this->boardMapper, $this->cardMapper, $this->attachmentService, $this->attachmentMapper, $this->stackMapper);
+		$this->deckShareProvider = $this->createMock(DeckShareProvider::class);
+		$this->deleteCron = new DeleteCron(
+			$this->timeFactory,
+			$this->boardMapper,
+			$this->cardMapper,
+			$this->attachmentService,
+			$this->attachmentMapper,
+			$this->stackMapper,
+			$this->deckShareProvider,
+		);
 	}
 
 	protected function getBoard($id) {