diff --git a/Shared/Infrastructure/Scripts/scan-malformed-lists.php b/Shared/Infrastructure/Scripts/scan-malformed-lists.php
new file mode 100644
index 00000000..6da08bf0
--- /dev/null
+++ b/Shared/Infrastructure/Scripts/scan-malformed-lists.php
@@ -0,0 +1,307 @@
+<?php
+/**
+ * Script de Diagnóstico: Listas HTML Mal Formadas
+ *
+ * PROPÓSITO: Identificar posts con estructura de listas inválida
+ * - <ul> conteniendo <ul> como hijo directo (en lugar de dentro de <li>)
+ * - <ol> conteniendo <ol> como hijo directo
+ *
+ * BASE DE DATOS: preciosunitarios_seo
+ * TABLA: datos_seo_pagina
+ * CAMPO: html
+ *
+ * IMPORTANTE: Este script SOLO LEE, no modifica ningún dato.
+ *
+ * @package ROI_Theme
+ * @since Phase 4.4 Accessibility
+ */
+
+// Configuración de errores para debugging
+error_reporting(E_ALL);
+ini_set('display_errors', 1);
+ini_set('memory_limit', '512M');
+set_time_limit(300); // 5 minutos máximo
+
+// Credenciales de base de datos (ajustar según servidor)
+$db_config = [
+    'host'     => 'localhost',
+    'database' => 'preciosunitarios_seo',
+    'username' => 'root',  // Cambiar en producción
+    'password' => '',      // Cambiar en producción
+    'charset'  => 'utf8mb4'
+];
+
+// Patrones regex para detectar listas mal formadas
+$malformed_patterns = [
+    // <ul> seguido directamente de <ul> (sin estar dentro de <li>)
+    'ul_direct_ul' => '/<ul[^>]*>\s*(?:<li[^>]*>.*?<\/li>\s*)*<ul/is',
+
+    // Patrón más específico: </li> seguido de <ul> (hermanos en lugar de anidados)
+    'li_sibling_ul' => '/<\/li>\s*<ul[^>]*>/is',
+
+    // <ol> seguido directamente de <ol>
+    'ol_direct_ol' => '/<ol[^>]*>\s*(?:<li[^>]*>.*?<\/li>\s*)*<ol/is',
+
+    // </li> seguido de <ol> (hermanos)
+    'li_sibling_ol' => '/<\/li>\s*<ol[^>]*>/is',
+];
+
+/**
+ * Conectar a la base de datos
+ */
+function connectDatabase(array $config): ?mysqli {
+    $conn = new mysqli(
+        $config['host'],
+        $config['username'],
+        $config['password'],
+        $config['database']
+    );
+
+    if ($conn->connect_error) {
+        echo "Error de conexión: " . $conn->connect_error . "\n";
+        return null;
+    }
+
+    $conn->set_charset($config['charset']);
+    return $conn;
+}
+
+/**
+ * Analizar HTML en busca de listas mal formadas
+ */
+function analyzeMalformedLists(string $html, array $patterns): array {
+    $issues = [];
+
+    foreach ($patterns as $pattern_name => $pattern) {
+        if (preg_match_all($pattern, $html, $matches, PREG_OFFSET_CAPTURE)) {
+            foreach ($matches[0] as $match) {
+                $position = $match[1];
+                $context = getContextAroundPosition($html, $position, 100);
+
+                $issues[] = [
+                    'type' => $pattern_name,
+                    'position' => $position,
+                    'context' => $context
+                ];
+            }
+        }
+    }
+
+    return $issues;
+}
+
+/**
+ * Obtener contexto alrededor de una posición
+ */
+function getContextAroundPosition(string $html, int $position, int $length = 100): string {
+    $start = max(0, $position - $length);
+    $end = min(strlen($html), $position + $length);
+
+    $context = substr($html, $start, $end - $start);
+
+    // Limpiar para mostrar
+    $context = preg_replace('/\s+/', ' ', $context);
+    $context = htmlspecialchars($context);
+
+    if ($start > 0) {
+        $context = '...' . $context;
+    }
+    if ($end < strlen($html)) {
+        $context .= '...';
+    }
+
+    return $context;
+}
+
+/**
+ * Contar total de listas en el HTML
+ */
+function countListElements(string $html): array {
+    $ul_count = preg_match_all('/<ul[^>]*>/i', $html);
+    $ol_count = preg_match_all('/<ol[^>]*>/i', $html);
+    $li_count = preg_match_all('/<li[^>]*>/i', $html);
+
+    return [
+        'ul' => $ul_count,
+        'ol' => $ol_count,
+        'li' => $li_count
+    ];
+}
+
+// ============================================
+// EJECUCIÓN PRINCIPAL
+// ============================================
+
+echo "==============================================\n";
+echo "  DIAGNÓSTICO: Listas HTML Mal Formadas\n";
+echo "  Base de datos: {$db_config['database']}\n";
+echo "  Tabla: datos_seo_pagina\n";
+echo "  Fecha: " . date('Y-m-d H:i:s') . "\n";
+echo "==============================================\n\n";
+
+// Conectar
+$conn = connectDatabase($db_config);
+if (!$conn) {
+    exit(1);
+}
+
+echo "✓ Conexión establecida\n\n";
+
+// Obtener estructura de la tabla
+echo "Verificando estructura de tabla...\n";
+$result = $conn->query("DESCRIBE datos_seo_pagina");
+if ($result) {
+    echo "Columnas encontradas:\n";
+    while ($row = $result->fetch_assoc()) {
+        echo "  - {$row['Field']} ({$row['Type']})\n";
+    }
+    echo "\n";
+}
+
+// Contar registros totales
+$result = $conn->query("SELECT COUNT(*) as total FROM datos_seo_pagina WHERE html IS NOT NULL AND html != ''");
+$total = $result->fetch_assoc()['total'];
+echo "Total de registros con HTML: {$total}\n\n";
+
+// Procesar en lotes
+$batch_size = 100;
+$offset = 0;
+$affected_posts = [];
+$total_issues = 0;
+$processed = 0;
+
+echo "Iniciando análisis...\n";
+echo "─────────────────────────────────────────────\n";
+
+while ($offset < $total) {
+    $query = "SELECT id, url, html FROM datos_seo_pagina
+              WHERE html IS NOT NULL AND html != ''
+              ORDER BY id
+              LIMIT {$batch_size} OFFSET {$offset}";
+
+    $result = $conn->query($query);
+
+    if (!$result) {
+        echo "Error en consulta: " . $conn->error . "\n";
+        break;
+    }
+
+    while ($row = $result->fetch_assoc()) {
+        $processed++;
+        $id = $row['id'];
+        $url = $row['url'] ?? 'N/A';
+        $html = $row['html'];
+
+        $issues = analyzeMalformedLists($html, $malformed_patterns);
+
+        if (!empty($issues)) {
+            $list_counts = countListElements($html);
+
+            $affected_posts[] = [
+                'id' => $id,
+                'url' => $url,
+                'issues' => $issues,
+                'list_counts' => $list_counts
+            ];
+
+            $total_issues += count($issues);
+
+            // Mostrar progreso para posts afectados
+            echo "\n[ID: {$id}] " . count($issues) . " problema(s) encontrado(s)\n";
+            echo "URL: {$url}\n";
+            echo "Listas: UL={$list_counts['ul']}, OL={$list_counts['ol']}, LI={$list_counts['li']}\n";
+
+            foreach ($issues as $idx => $issue) {
+                echo "  Problema " . ($idx + 1) . ": {$issue['type']} (pos: {$issue['position']})\n";
+            }
+        }
+
+        // Mostrar progreso cada 500 registros
+        if ($processed % 500 == 0) {
+            echo "\rProcesados: {$processed}/{$total}...";
+        }
+    }
+
+    $offset += $batch_size;
+}
+
+echo "\n\n";
+echo "==============================================\n";
+echo "  RESUMEN DEL ANÁLISIS\n";
+echo "==============================================\n\n";
+
+echo "Registros analizados: {$processed}\n";
+echo "Posts con problemas: " . count($affected_posts) . "\n";
+echo "Total de incidencias: {$total_issues}\n\n";
+
+if (count($affected_posts) > 0) {
+    echo "─────────────────────────────────────────────\n";
+    echo "DETALLE DE POSTS AFECTADOS\n";
+    echo "─────────────────────────────────────────────\n\n";
+
+    // Agrupar por tipo de problema
+    $by_type = [];
+    foreach ($affected_posts as $post) {
+        foreach ($post['issues'] as $issue) {
+            $type = $issue['type'];
+            if (!isset($by_type[$type])) {
+                $by_type[$type] = [];
+            }
+            $by_type[$type][] = $post['id'];
+        }
+    }
+
+    echo "Por tipo de problema:\n";
+    foreach ($by_type as $type => $ids) {
+        $unique_ids = array_unique($ids);
+        echo "  - {$type}: " . count($unique_ids) . " posts\n";
+    }
+
+    echo "\n─────────────────────────────────────────────\n";
+    echo "LISTA DE IDs AFECTADOS (para revisión manual)\n";
+    echo "─────────────────────────────────────────────\n\n";
+
+    $ids_list = array_column($affected_posts, 'id');
+    echo "IDs: " . implode(', ', $ids_list) . "\n";
+
+    // Generar archivo de reporte
+    $report_file = __DIR__ . '/malformed-lists-report-' . date('Ymd-His') . '.json';
+    $report_data = [
+        'generated_at' => date('Y-m-d H:i:s'),
+        'database' => $db_config['database'],
+        'table' => 'datos_seo_pagina',
+        'total_analyzed' => $processed,
+        'total_affected' => count($affected_posts),
+        'total_issues' => $total_issues,
+        'by_type' => array_map(function($ids) {
+            return array_values(array_unique($ids));
+        }, $by_type),
+        'affected_posts' => $affected_posts
+    ];
+
+    if (file_put_contents($report_file, json_encode($report_data, JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE))) {
+        echo "\n✓ Reporte JSON guardado en:\n  {$report_file}\n";
+    }
+
+    // Muestra de contexto para análisis
+    echo "\n─────────────────────────────────────────────\n";
+    echo "MUESTRA DE CONTEXTO (primeros 3 posts)\n";
+    echo "─────────────────────────────────────────────\n\n";
+
+    $sample = array_slice($affected_posts, 0, 3);
+    foreach ($sample as $post) {
+        echo "POST ID: {$post['id']}\n";
+        echo "URL: {$post['url']}\n";
+        foreach ($post['issues'] as $idx => $issue) {
+            echo "  [{$issue['type']}]\n";
+            echo "  Contexto: {$issue['context']}\n\n";
+        }
+        echo "───────────────────────\n";
+    }
+
+} else {
+    echo "✓ No se encontraron listas mal formadas.\n";
+}
+
+$conn->close();
+echo "\n✓ Análisis completado.\n";