diff --git a/lib/private/Command/CallableJob.php b/lib/private/Command/CallableJob.php
index 56cddb4bb592..ec7d61deafa1 100644
--- a/lib/private/Command/CallableJob.php
+++ b/lib/private/Command/CallableJob.php
@@ -25,7 +25,8 @@
 
 class CallableJob extends QueuedJob {
 	protected function run($serializedCallable) {
-		$callable = \unserialize($serializedCallable);
+		// Restrict to prevent PHP Object Injection; arbitrary PHP objects cannot be callables.
+		$callable = \unserialize($serializedCallable, ['allowed_classes' => false]);
 		if (\is_callable($callable)) {
 			$callable();
 		} else {
diff --git a/lib/private/Command/ClosureJob.php b/lib/private/Command/ClosureJob.php
index b0964c503ef4..e04db985a498 100644
--- a/lib/private/Command/ClosureJob.php
+++ b/lib/private/Command/ClosureJob.php
@@ -25,7 +25,11 @@
 
 class ClosureJob extends QueuedJob {
 	protected function run($serializedCallable) {
-		$serializedClosure = \unserialize($serializedCallable);
+		// Use allowed_classes => true: SerializableClosure's serialized form nests internal
+		// classes (e.g. Laravel\SerializableClosure\Serializers\Native) that would be blocked
+		// by a strict allow-list, silently producing __PHP_Incomplete_Class. The existing
+		// method_exists('getClosure') guard below prevents execution of any non-closure object.
+		$serializedClosure = \unserialize($serializedCallable, ['allowed_classes' => true]);
 		if (\method_exists($serializedClosure, 'getClosure')) {
 			$callable = $serializedClosure->getClosure();
 			if (\is_callable($callable)) {
diff --git a/lib/private/Command/CommandJob.php b/lib/private/Command/CommandJob.php
index a935300303b8..7aed8a5ac2c8 100644
--- a/lib/private/Command/CommandJob.php
+++ b/lib/private/Command/CommandJob.php
@@ -29,7 +29,12 @@
  */
 class CommandJob extends QueuedJob {
 	protected function run($serializedCommand) {
-		$command = \unserialize($serializedCommand);
+		// allowed_classes => true: PHP's allowed_classes performs exact class-name
+		// matching and does not resolve interface hierarchies. Passing ICommand::class
+		// (an interface) would silently produce __PHP_Incomplete_Class for every real
+		// payload. The existing instanceof check below still ensures only valid
+		// ICommand objects are handled.
+		$command = \unserialize($serializedCommand, ['allowed_classes' => true]);
 		if ($command instanceof ICommand) {
 			$command->handle();
 		} else {
diff --git a/lib/private/Command/QueueBus.php b/lib/private/Command/QueueBus.php
index 1145becb6e52..9f120b3770f8 100644
--- a/lib/private/Command/QueueBus.php
+++ b/lib/private/Command/QueueBus.php
@@ -57,7 +57,12 @@ private function runCommand($command) {
 			if (\strlen($serialized) > 4000) {
 				throw new \InvalidArgumentException('Trying to push a command which serialized form can not be stored in the database (>4000 character)');
 			}
-			$unserialized = \unserialize($serialized);
+			// allowed_classes => true: PHP's allowed_classes does not resolve interface
+			// hierarchies, so passing ICommand::class (an interface) would produce
+			// __PHP_Incomplete_Class. The serialized value was just produced from
+			// $command above in this same method — it is a pure in-memory round-trip
+			// and not an external attack surface.
+			$unserialized = \unserialize($serialized, ['allowed_classes' => true]);
 			$unserialized->handle();
 		} else {
 			$command();