diff --git a/models/BulkOperationsModel.php b/models/BulkOperationsModel.php
index a5d68ef..47dee2c 100644
--- a/models/BulkOperationsModel.php
+++ b/models/BulkOperationsModel.php
@@ -33,6 +33,23 @@ class BulkOperationsModel
         return $this->workflowModel;
     }
 
+    /**
+     * Re-fetch a ticket row inside the current transaction with a row lock
+     * (FOR UPDATE), so a concurrent transaction touching the same row blocks
+     * until this one commits or rolls back instead of both validating
+     * against the same stale snapshot. Must be called after
+     * begin_transaction() and before the row is written.
+     */
+    private function lockTicketForUpdate(string $ticketId): ?array
+    {
+        $stmt = $this->conn->prepare("SELECT * FROM tickets WHERE ticket_id = ? FOR UPDATE");
+        $stmt->bind_param('s', $ticketId);
+        $stmt->execute();
+        $row = $stmt->get_result()->fetch_assoc();
+        $stmt->close();
+        return $row ?: null;
+    }
+
     /**
      * The status a bulk operation is trying to move tickets into, or null for
      * operations that don't change status.
@@ -183,13 +200,27 @@ class BulkOperationsModel
                 $success = false;
 
                 try {
+                    // Re-fetch and row-lock the ticket inside the transaction for any
+                    // operation that validates against or reads its current fields —
+                    // the pre-transaction $ticketsById snapshot (loaded before
+                    // begin_transaction()) can be stale by the time we get here if a
+                    // concurrent request (a single-ticket edit, or another bulk op)
+                    // changed the row in between. Validating a transition against a
+                    // stale status, or writing back stale title/description/etc.,
+                    // could silently bypass Workflow Designer rules or clobber a
+                    // concurrent edit. FOR UPDATE blocks a concurrent transaction
+                    // from reading/writing this row until ours commits or rolls back.
+                    $needsCurrentTicket = $targetStatus !== null || $operation['operation_type'] === 'bulk_priority';
+                    $currentTicket = $needsCurrentTicket
+                        ? $this->lockTicketForUpdate($ticketId)
+                        : ($ticketsById[$ticketId] ?? null);
+
                     // bulk_status / bulk_close enforce the same Workflow Designer
                     // rules as the single-ticket path: a transition the designer
                     // doesn't define is refused, and requires_comment is honoured
                     // (checked up front, above). requires_admin is satisfied because
                     // api/bulk_operation.php already gates the endpoint on admin.
                     if ($targetStatus !== null) {
-                        $currentTicket = $ticketsById[$ticketId] ?? null;
                         if ($currentTicket && $currentTicket['status'] === $targetStatus) {
                             // Already in the requested state — nothing to do, and
                             // reporting a no-op as a failure would just confuse.
@@ -211,8 +242,7 @@ class BulkOperationsModel
 
                     switch ($operation['operation_type']) {
                         case 'bulk_close':
-                            // Get current ticket from pre-loaded batch
-                            $currentTicket = $ticketsById[$ticketId] ?? null;
+                            // $currentTicket is the fresh, row-locked read from above.
                             if ($currentTicket) {
                                 $updateResult = $ticketModel->updateTicket([
                                 'ticket_id' => $ticketId,
@@ -264,7 +294,7 @@ class BulkOperationsModel
 
                         case 'bulk_priority':
                             if (isset($parameters['priority'])) {
-                                $currentTicket = $ticketsById[$ticketId] ?? null;
+                                // $currentTicket is the fresh, row-locked read from above.
                                 if ($currentTicket) {
                                     $updateResult = $ticketModel->updateTicket([
                                     'ticket_id' => $ticketId,
@@ -292,7 +322,7 @@ class BulkOperationsModel
 
                         case 'bulk_status':
                             if (isset($parameters['status'])) {
-                                $currentTicket = $ticketsById[$ticketId] ?? null;
+                                // $currentTicket is the fresh, row-locked read from above.
                                 if ($currentTicket) {
                                     $updateResult = $ticketModel->updateTicket([
                                     'ticket_id' => $ticketId,