The SentinelOne Annual Threat Report - A Defenders Guide from the FrontlinesThe SentinelOne Annual Threat ReportGet the Report
Experiencing a Breach?Blog
Get StartedContact Us
SentinelOne
  • Platform
    Platform Overview
    • Singularity Platform
      Welcome to Integrated Enterprise Security
    • AI for Security
      Leading the Way in AI-Powered Security Solutions
    • Securing AI
      Accelerate AI Adoption with Secure AI Tools, Apps, and Agents.
    • How It Works
      The Singularity XDR Difference
    • Singularity Marketplace
      One-Click Integrations to Unlock the Power of XDR
    • Pricing & Packaging
      Comparisons and Guidance at a Glance
    Data & AI
    • Purple AI
      Accelerate SecOps with Generative AI
    • Singularity Hyperautomation
      Easily Automate Security Processes
    • AI-SIEM
      The AI SIEM for the Autonomous SOC
    • AI Data Pipelines
      Security Data Pipeline for AI SIEM and Data Optimization
    • Singularity Data Lake
      AI-Powered, Unified Data Lake
    • Singularity Data Lake for Log Analytics
      Seamlessly Ingest Data from On-Prem, Cloud or Hybrid Environments
    Endpoint Security
    • Singularity Endpoint
      Autonomous Prevention, Detection, and Response
    • Singularity XDR
      Native & Open Protection, Detection, and Response
    • Singularity RemoteOps Forensics
      Orchestrate Forensics at Scale
    • Singularity Threat Intelligence
      Comprehensive Adversary Intelligence
    • Singularity Vulnerability Management
      Application & OS Vulnerability Management
    • Singularity Identity
      Identity Threat Detection and Response
    Cloud Security
    • Singularity Cloud Security
      Block Attacks with an AI-Powered CNAPP
    • Singularity Cloud Native Security
      Secure Cloud and Development Resources
    • Singularity Cloud Workload Security
      Real-Time Cloud Workload Protection Platform
    • Singularity Cloud Data Security
      AI-Powered Threat Detection for Cloud Storage
    • Singularity Cloud Security Posture Management
      Detect and Remediate Cloud Misconfigurations
    Securing AI
    • Prompt Security
      Secure AI Tools Across Your Enterprise
  • Why SentinelOne?
    Why SentinelOne?
    • Why SentinelOne?
      Cybersecurity Built for What’s Next
    • Our Customers
      Trusted by the World’s Leading Enterprises
    • Industry Recognition
      Tested and Proven by the Experts
    • About Us
      The Industry Leader in Autonomous Cybersecurity
    Compare SentinelOne
    • Arctic Wolf
    • Broadcom
    • CrowdStrike
    • Cybereason
    • Microsoft
    • Palo Alto Networks
    • Sophos
    • Splunk
    • Trellix
    • Trend Micro
    • Wiz
    Verticals
    • Energy
    • Federal Government
    • Finance
    • Healthcare
    • Higher Education
    • K-12 Education
    • Manufacturing
    • Retail
    • State and Local Government
  • Services
    Managed Services
    • Managed Services Overview
      Wayfinder Threat Detection & Response
    • Threat Hunting
      World-Class Expertise and Threat Intelligence
    • Managed Detection & Response
      24/7/365 Expert MDR Across Your Entire Environment
    • Incident Readiness & Response
      DFIR, Breach Readiness, & Compromise Assessments
    Support, Deployment, & Health
    • Technical Account Management
      Customer Success with Personalized Service
    • SentinelOne GO
      Guided Onboarding & Deployment Advisory
    • SentinelOne University
      Live and On-Demand Training
    • Services Overview
      Comprehensive Solutions for Seamless Security Operations
    • SentinelOne Community
      Community Login
  • Partners
    Our Network
    • MSSP Partners
      Succeed Faster with SentinelOne
    • Singularity Marketplace
      Extend the Power of S1 Technology
    • Cyber Risk Partners
      Enlist Pro Response and Advisory Teams
    • Technology Alliances
      Integrated, Enterprise-Scale Solutions
    • SentinelOne for AWS
      Hosted in AWS Regions Around the World
    • Channel Partners
      Deliver the Right Solutions, Together
    • SentinelOne for Google Cloud
      Unified, Autonomous Security Giving Defenders the Advantage at Global Scale
    • Partner Locator
      Your Go-to Source for Our Top Partners in Your Region
    Partner Portal→
  • Resources
    Resource Center
    • Case Studies
    • Data Sheets
    • eBooks
    • Reports
    • Videos
    • Webinars
    • Whitepapers
    • Events
    View All Resources→
    Blog
    • Feature Spotlight
    • For CISO/CIO
    • From the Front Lines
    • Identity
    • Cloud
    • macOS
    • SentinelOne Blog
    Blog→
    Tech Resources
    • SentinelLABS
    • Ransomware Anthology
    • Cybersecurity 101
  • About
    About SentinelOne
    • About SentinelOne
      The Industry Leader in Cybersecurity
    • Investor Relations
      Financial Information & Events
    • SentinelLABS
      Threat Research for the Modern Threat Hunter
    • Careers
      The Latest Job Opportunities
    • Press & News
      Company Announcements
    • Cybersecurity Blog
      The Latest Cybersecurity Threats, News, & More
    • FAQ
      Get Answers to Our Most Frequently Asked Questions
    • DataSet
      The Live Data Platform
    • S Foundation
      Securing a Safer Future for All
    • S Ventures
      Investing in the Next Generation of Security, Data and AI
  • Pricing
Get StartedContact Us
CVE Vulnerability Database
Vulnerability Database/CVE-2025-53805

CVE-2025-53805: Windows 11 22h2 DOS Vulnerability

CVE-2025-53805 is a denial of service vulnerability in Windows 11 22h2 caused by an out-of-bounds read in IIS. Attackers can exploit this flaw remotely to disrupt services. This article covers technical details, impact, and mitigation.

Updated: May 15, 2026

CVE-2025-53805 Overview

CVE-2025-53805 is an out-of-bounds read vulnerability [CWE-125] in Windows Internet Information Services (IIS). The flaw allows an unauthenticated remote attacker to trigger a denial of service condition over the network. Microsoft disclosed the issue on September 9, 2025, affecting multiple supported versions of Windows 11 and Windows Server.

The vulnerability requires no privileges and no user interaction. Successful exploitation reads memory outside the bounds of allocated buffers within the IIS worker process, causing the service to crash. Confidentiality and integrity are not impacted, but availability of hosted web applications is.

Critical Impact

An unauthenticated network attacker can crash IIS-hosted services on affected Windows systems, disrupting web applications and APIs without requiring credentials or user interaction.

Affected Products

  • Microsoft Windows 11 (22H2, 23H2, 24H2)
  • Microsoft Windows Server 2022 and Server 2022 23H2
  • Microsoft Windows Server 2025

Discovery Timeline

  • 2025-09-09 - CVE-2025-53805 published to NVD by Microsoft
  • 2025-10-02 - Last updated in NVD database

Technical Details for CVE-2025-53805

Vulnerability Analysis

The vulnerability is classified as an out-of-bounds read [CWE-125] in the Windows Internet Information Services (IIS) component. IIS is Microsoft's web server platform used to host websites, web applications, and REST APIs on Windows Server and Windows desktop systems.

An out-of-bounds read occurs when code reads data past the end, or before the beginning, of an allocated buffer. When IIS processes a malformed network request, it dereferences memory outside the expected buffer boundary. This produces an access violation that terminates the worker process serving HTTP requests.

Because the attack vector is network-based and requires neither authentication nor user interaction, any reachable IIS endpoint is exposed. The scope is unchanged and only the availability impact is high. Confidentiality and integrity remain unaffected by this specific flaw.

Root Cause

The root cause is missing or incorrect bounds checking when IIS parses attacker-supplied input from an incoming HTTP request. Without strict length validation against allocated buffer sizes, the parser reads beyond the intended memory region. Microsoft has not published low-level technical specifics beyond the advisory.

Attack Vector

An attacker sends a crafted HTTP request to an exposed IIS service over the network. Processing the malformed request triggers the out-of-bounds read in the IIS worker process. The worker terminates, dropping all in-flight connections and rendering hosted sites unreachable until the process restarts. Repeated requests can sustain the denial of service condition.

No public proof-of-concept exploit is currently associated with this CVE, and it is not listed in the CISA Known Exploited Vulnerabilities catalog. See the Microsoft Security Advisory for vendor guidance.

Detection Methods for CVE-2025-53805

Indicators of Compromise

  • Unexpected crashes or restarts of the IIS worker process (w3wp.exe) recorded in the Windows Application event log.
  • Windows Error Reporting (WER) entries referencing access violations within IIS modules.
  • Spikes in HTTP 5xx responses or sudden connection resets from IIS-hosted endpoints.
  • Inbound HTTP requests containing malformed headers or oversized fields immediately preceding worker process termination.

Detection Strategies

  • Monitor Windows Event IDs 1000 and 1001 for w3wp.exe faults and correlate with inbound request logs from IIS (%SystemDrive%\inetpub\logs\LogFiles).
  • Alert on repeated IIS application pool recycles within short time windows, which can indicate exploitation attempts.
  • Inspect WAF and reverse proxy logs for anomalous HTTP request patterns targeting IIS endpoints from a small set of source IPs.

Monitoring Recommendations

  • Forward IIS access logs, HTTPERR logs, and Windows Application event logs to a centralized SIEM for correlation.
  • Establish a baseline for application pool restart frequency and alert on deviations.
  • Track CPU, memory, and connection count metrics for IIS hosts to identify availability degradation in real time.

How to Mitigate CVE-2025-53805

Immediate Actions Required

  • Apply the Microsoft security update referenced in the Microsoft Security Advisory to all affected Windows 11 and Windows Server systems.
  • Inventory all internet-facing IIS instances and prioritize patching of externally reachable servers.
  • Place IIS hosts behind a web application firewall capable of dropping malformed HTTP requests until patching completes.

Patch Information

Microsoft has issued patches for all affected products through its standard Patch Tuesday channel. Administrators should obtain the relevant cumulative update from Windows Update, WSUS, or the Microsoft Update Catalog. Verify update installation by checking the system's installed update history and confirming the build number matches the post-patch revision listed in the advisory.

Workarounds

  • Restrict access to IIS endpoints using network access control lists, host-based firewalls, or VPN-only access where feasible.
  • Configure IIS request filtering to reject requests with abnormal header sizes, lengths, or unsupported verbs.
  • Enable rapid application pool recycling and automatic worker process restart to reduce downtime if exploitation occurs before patching.
bash
# Configuration example: enable IIS request filtering limits via appcmd
appcmd set config /section:requestFiltering /requestLimits.maxAllowedContentLength:30000000
appcmd set config /section:requestFiltering /requestLimits.maxUrl:4096
appcmd set config /section:requestFiltering /requestLimits.maxQueryString:2048

Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.

  • Vulnerability Details
  • TypeDOS

  • Vendor/TechWindows

  • SeverityHIGH

  • CVSS Score7.5

  • EPSS Probability0.18%

  • Known ExploitedNo
  • CVSS Vector
  • CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
  • Impact Assessment
  • ConfidentialityLow
  • IntegrityNone
  • AvailabilityHigh
  • CWE References
  • CWE-125
  • Vendor Resources
  • Microsoft Security Advisory
  • Related CVEs
  • CVE-2026-40401: Windows 10 1607 DOS Vulnerability

  • CVE-2026-40405: Windows 11 24h2 DOS Vulnerability

  • CVE-2026-40413: Windows 10 1607 DOS Vulnerability

  • CVE-2026-40414: Windows 10 1607 DOS Vulnerability
Default Legacy - Prefooter | Experience the World’s Most Advanced Cybersecurity Platform

Experience the Most Advanced Cybersecurity Platform

See how the world’s most intelligent, autonomous cybersecurity platform can protect your organization today and into the future.

Try SentinelOne
  • Get Started
  • Get a Demo
  • Product Tour
  • Why SentinelOne
  • Pricing & Packaging
  • FAQ
  • Contact
  • Contact Us
  • Customer Support
  • SentinelOne Status
  • Language
  • Platform
  • Singularity Platform
  • Singularity Endpoint
  • Singularity Cloud
  • Singularity AI-SIEM
  • Singularity Identity
  • Singularity Marketplace
  • Purple AI
  • Services
  • Wayfinder TDR
  • SentinelOne GO
  • Technical Account Management
  • Support Services
  • Verticals
  • Energy
  • Federal Government
  • Finance
  • Healthcare
  • Higher Education
  • K-12 Education
  • Manufacturing
  • Retail
  • State and Local Government
  • Cybersecurity for SMB
  • Resources
  • Blog
  • Labs
  • Case Studies
  • Videos
  • Product Tours
  • Events
  • Cybersecurity 101
  • eBooks
  • Webinars
  • Whitepapers
  • Press
  • News
  • Ransomware Anthology
  • Company
  • About Us
  • Our Customers
  • Careers
  • Partners
  • Legal & Compliance
  • Security & Compliance
  • Investor Relations
  • S Foundation
  • S Ventures

©2026 SentinelOne, All Rights Reserved.

Privacy Notice Terms of Use

English