EUVD-2026-56620
GHSA-mffm-85p4-qvf5
Severity by source
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Standard local user account suffices (PR:L, AV:L); symlink exploitation imposes no special conditions (AC:L); successful escalation to SYSTEM yields full system compromise (C:H/I:H/A:H).
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
3DescriptionCVE.org
Improper link resolution before file access ('link following') in Windows Accessibility Infrastructure (ATBroker.exe) allows an authorized attacker to elevate privileges locally.
AnalysisAI
Local privilege escalation in Windows Accessibility Infrastructure (ATBroker.exe) affects a broad range of Windows 10, Windows 11, and Windows Server releases through a symlink-following flaw (CWE-59). An authenticated local attacker can manipulate file system links to redirect ATBroker.exe file access operations, enabling elevation from a standard user account to SYSTEM-level privileges across default Windows installations. No public exploit has been identified at time of analysis; however, Microsoft has released a patch and the breadth of affected builds makes timely remediation critical.
Technical ContextAI
ATBroker.exe (Assistive Technology Broker) is a core Windows accessibility component responsible for coordinating and launching assistive technologies such as screen readers, magnifiers, and on-screen keyboards. It operates with elevated privileges as part of the Windows Accessibility Infrastructure and is present by default in standard Windows installations. CWE-59 (Improper Link Resolution Before File Access - Link Following) describes a class of vulnerabilities in which software opens a file or directory resource without properly preventing that resource from being replaced or redirected via a symbolic link, hard link, or junction point before the privileged operation completes. In this instance, ATBroker.exe fails to safely validate or resolve file paths before performing privileged file access operations, allowing an attacker-controlled link to redirect those operations to an arbitrary target. Because ATBroker.exe runs with elevated context, the redirected access occurs with permissions the attacker does not ordinarily hold, enabling overwrite or disclosure of protected system resources.
RemediationAI
Apply the Microsoft security update for CVE-2026-61358 via Windows Update, WSUS, or Microsoft Update Catalog, targeting the following minimum fixed builds per version: 10.0.17763.9115 for Windows Server 2019 and Windows 10 Version 1809; 10.0.19044.7663 for Windows 10 Version 21H2; 10.0.19045.7663 for Windows 10 Version 22H2; 10.0.20348.5499 for Windows Server 2022; 10.0.22631.7517 for Windows 11 Version 23H2; 10.0.26100.9168 for Windows 11 Version 24H2; 10.0.26100.33296 for Windows Server 2025; 10.0.26200.9168 for Windows 11 Version 25H2; and 10.0.28000.2704 for Windows 11 version 26H1. The full vendor advisory is at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-61358. Where immediate patching is not feasible, restricting interactive logon and Remote Desktop access to explicitly trusted, privileged accounts reduces the pool of potential attackers - note this is not a complete mitigation for environments with shared workstations or kiosk deployments where standard-user local sessions are a design requirement. Deploying Sysmon with file creation and symlink monitoring rules, or enabling Windows Audit Object Access policies targeting ATBroker.exe file operations, can serve as a detection layer pending patch deployment.
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External POC / Exploit Code
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