📄 Description (English)
Time-of-check time-of-use (toctou) race condition in Windows HTTP.sys allows an authorized attacker to elevate privileges locally.
🤖 AI Executive Summary
CVE-2026-21240 is a time-of-check time-of-use (TOCTOU) race condition in Windows HTTP.sys affecting Windows 10 and 11 versions, allowing authorized local attackers to escalate privileges. With a CVSS score of 7.8 and no public exploit currently available, this vulnerability poses a significant risk to Saudi organizations relying on Windows infrastructure. Immediate patching is critical to prevent potential lateral movement and unauthorized system access.
📄 Description (Arabic)
🤖 AI Intelligence Analysis Analyzed: Apr 28, 2026 12:03
🇸🇦 Saudi Arabia Impact Assessment
This vulnerability primarily impacts Saudi government agencies, banking sector (SAMA-regulated institutions), healthcare organizations, and large enterprises running Windows 10/11 infrastructure. Government entities using Windows-based systems for critical operations face elevated risk of privilege escalation attacks. Banking and financial institutions are particularly vulnerable as HTTP.sys is fundamental to web service operations. Telecom operators (STC, Mobily) and energy sector organizations (ARAMCO subsidiaries) managing Windows-based infrastructure could experience service disruption or unauthorized access. The local attack vector requires prior system access, limiting exposure but increasing risk for insider threats.
🏢 Affected Saudi Sectors
Government
Banking and Financial Services
Healthcare
Energy and Utilities
Telecommunications
Education
Large Enterprises
🎯 MITRE ATT&CK Techniques
⚖️ Saudi Risk Score (AI)
7.2
/ 10.0
🔧 Remediation Steps (English)
Immediate Actions:
1. Identify all Windows 10 (versions 1809, 21H2, 22H2) and Windows 11 (23H2) systems in your environment using asset management tools
2. Prioritize patching for systems with elevated privileges and multi-user access
3. Implement access controls to restrict local system access to authorized personnel only
Patching Guidance:
1. Apply Microsoft security updates immediately upon availability through Windows Update or WSUS
2. For enterprise environments, deploy patches through SCCM or equivalent patch management solutions
3. Test patches in non-production environments before broad deployment
4. Verify HTTP.sys functionality post-patching
Compensating Controls (if patching delayed):
1. Implement application whitelisting to restrict execution of privilege escalation tools
2. Enable Windows Defender Exploit Guard with Attack Surface Reduction rules
3. Monitor and restrict local administrative access through privileged access management (PAM) solutions
4. Implement file integrity monitoring on critical system files
Detection Rules:
1. Monitor for suspicious HTTP.sys process behavior and file access patterns
2. Alert on failed privilege escalation attempts in Windows Event Viewer (Event ID 4688, 4689)
3. Track unusual process creation from HTTP.sys or related services
4. Monitor for race condition exploitation patterns in file system operations
🔧 خطوات المعالجة (العربية)
الإجراءات الفورية:
1. تحديد جميع أنظمة Windows 10 (الإصدارات 1809 و21H2 و22H2) و Windows 11 (23H2) في بيئتك باستخدام أدوات إدارة الأصول
2. إعطاء الأولوية لتصحيح الأنظمة ذات الامتيازات المرتفعة والوصول متعدد المستخدمين
3. تنفيذ عناصر التحكم في الوصول لتقييد الوصول المحلي للنظام للموظفين المصرحين فقط
إرشادات التصحيح:
1. تطبيق تحديثات أمان Microsoft فورًا عند توفرها من خلال Windows Update أو WSUS
2. بالنسبة للبيئات الموجهة للمؤسسات، نشر التصحيحات من خلال SCCM أو حلول إدارة التصحيحات المكافئة
3. اختبار التصحيحات في بيئات غير الإنتاج قبل النشر الواسع
4. التحقق من وظائف HTTP.sys بعد التصحيح
عناصر التحكم البديلة (إذا تأخر التصحيح):
1. تنفيذ قائمة بيضاء للتطبيقات لتقييد تنفيذ أدوات تصعيد الامتيازات
2. تفعيل Windows Defender Exploit Guard مع قواعد تقليل سطح الهجوم
3. مراقبة وتقييد الوصول الإداري المحلي من خلال حلول إدارة الوصول المميز (PAM)
4. تنفيذ مراقبة سلامة الملفات على ملفات النظام الحرجة
قواعد الكشف:
1. مراقبة سلوك عملية HTTP.sys المريب وأنماط الوصول إلى الملفات
2. التنبيه على محاولات تصعيد الامتيازات الفاشلة في عارض أحداث Windows (معرف الحدث 4688 و4689)
3. تتبع إنشاء العملية غير المعتاد من HTTP.sys أو الخدمات ذات الصلة
4. مراقبة أنماط استغلال حالات التسابق في عمليات نظام الملفات
📋 Regulatory Compliance Mapping
🟢 NCA ECC 2024
A.5.1.1 - Information security policies and procedures
A.6.1.1 - Access control policy
A.6.2.1 - User registration and de-registration
A.8.2.1 - Classification of information
A.12.2.1 - Controls against malware
A.12.6.1 - Management of technical vulnerabilities
🔵 SAMA CSF
ID.AM-2 - Software platforms and applications within the organization are inventoried
PR.AC-1 - Identities and credentials are issued, managed, verified, revoked, and audited
PR.PT-1 - Security patches and updates are managed
DE.CM-8 - Vulnerability scans are performed
🟡 ISO 27001:2022
A.5.1 - Management direction for information security
A.6.1 - Internal organization
A.8.1 - Asset management
A.12.6 - Management of technical vulnerabilities
A.14.2 - Development and change management
🟣 PCI DSS v4.0.1
Requirement 2.2 - Configuration standards for system components
Requirement 6.2 - Security patches and updates
📦 Affected Products / CPE 18 entries
microsoft:windows_10_1809
microsoft:windows_10_1809
microsoft:windows_10_21h2
microsoft:windows_10_21h2
microsoft:windows_10_21h2
microsoft:windows_10_22h2
microsoft:windows_10_22h2
microsoft:windows_10_22h2
microsoft:windows_11_23h2
microsoft:windows_11_23h2
microsoft:windows_11_24h2
microsoft:windows_11_24h2
microsoft:windows_11_25h2
microsoft:windows_11_25h2
microsoft:windows_server_2019
microsoft:windows_server_2022
microsoft:windows_server_2022_23h2
microsoft:windows_server_2025