diff --git a/build/integration/sharees_features/sharees_user.feature b/build/integration/sharees_features/sharees_user.feature
index 057d63ec681..25cbd569fec 100644
--- a/build/integration/sharees_features/sharees_user.feature
+++ b/build/integration/sharees_features/sharees_user.feature
@@ -475,3 +475,23 @@ Feature: sharees_user
 		And "exact users" sharees returned are
 			| Test One | 0 | test1 | test@example.com |
 		And "users" sharees returned is empty
+
+	Scenario: Search for exact additional email returns exact user
+		Given user "test1" with displayname "Test One" exists
+		And As an "admin"
+		And sending "PUT" to "/cloud/users/test1" with
+			| key   | email            |
+			| value | test@example.com |
+		And sending "PUT" to "/cloud/users/test1" with
+			| key   | additional_mail  |
+			| value | test@example.org |
+		And user "user1" exists
+		And As an "user1"
+		When getting sharees for
+			| search   | test@example.org |
+			| itemType | file             |
+		Then the OCS status code should be "100"
+		And the HTTP status code should be "200"
+		And "exact users" sharees returned are
+			| Test One (test@example.org) | 0 | test1 | test@example.org |
+		And "users" sharees returned is empty
diff --git a/lib/private/Collaboration/Collaborators/UserPlugin.php b/lib/private/Collaboration/Collaborators/UserPlugin.php
index 3c1cd6a0775..91b6a0911b5 100644
--- a/lib/private/Collaboration/Collaborators/UserPlugin.php
+++ b/lib/private/Collaboration/Collaborators/UserPlugin.php
@@ -9,6 +9,7 @@ namespace OC\Collaboration\Collaborators;
 use OCP\Collaboration\Collaborators\ISearchPlugin;
 use OCP\Collaboration\Collaborators\ISearchResult;
 use OCP\Collaboration\Collaborators\SearchResultType;
+use OCP\DB\QueryBuilder\IQueryBuilder;
 use OCP\IAppConfig;
 use OCP\IDBConnection;
 use OCP\IGroupManager;
@@ -105,14 +106,16 @@ class UserPlugin implements ISearchPlugin {
 			if ($shareeEnumerationFullMatchEmail) {
 				$qb = $this->connection->getQueryBuilder();
 				$qb
-					->selectDistinct('uid')
+					->select('uid', 'value', 'name')
 					->from('accounts_data')
 					->where($qb->expr()->eq($qb->func()->lower('value'), $qb->createNamedParameter($lowerSearch)))
-					->andWhere($qb->expr()->eq('name', $qb->createNamedParameter('email')));
+					->andWhere($qb->expr()->in('name', $qb->createNamedParameter(['email', 'additional_mail'], IQueryBuilder::PARAM_STR_ARRAY)));
 				$result = $qb->executeQuery();
-				while ($uid = $result->fetchOne()) {
-					/** @var string $uid */
-					$users[$uid] = ['exact', $this->userManager->get($uid)];
+				while ($row = $result->fetch()) {
+					$uid = $row['uid'];
+					$email = $row['value'];
+					$isAdditional = $row['name'] === 'additional_mail';
+					$users[$uid] = ['exact', $this->userManager->get($uid), $isAdditional ? $email : null];
 				}
 				$result->closeCursor();
 			}
@@ -143,17 +146,25 @@ class UserPlugin implements ISearchPlugin {
 
 		$result = ['wide' => [], 'exact' => []];
 		foreach ($users as $match) {
-			[$type, $user] = $match;
+			$match[2] ??= null;
+			[$type, $user, $uniqueDisplayName] = $match;
+
+			$displayName = $user->getDisplayName();
+			if ($uniqueDisplayName !== null) {
+				$displayName .= ' (' . $uniqueDisplayName . ')';
+			}
+
 			$status = $userStatuses[$user->getUID()] ?? [];
+
 			$result[$type][] = [
-				'label' => $user->getDisplayName(),
+				'label' => $displayName,
 				'subline' => $status['message'] ?? '',
 				'icon' => 'icon-user',
 				'value' => [
 					'shareType' => IShare::TYPE_USER,
 					'shareWith' => $user->getUID(),
 				],
-				'shareWithDisplayNameUnique' => $user->getSystemEMailAddress() ?: $user->getUID(),
+				'shareWithDisplayNameUnique' => $uniqueDisplayName ?? $user->getSystemEMailAddress() ?: $user->getUID(),
 				'status' => $status,
 			];
 		}