CVE-2025-47181: Microsoft Edge Privilege Escalation Flaw

CVE-2025-47181 Overview

CVE-2025-47181 is a local privilege escalation vulnerability in Microsoft Edge Update, the component responsible for keeping the Chromium-based Edge browser current. The flaw stems from improper link resolution before file access, classified as [CWE-59]. An authorized attacker with local access can leverage symbolic or hard link manipulation to elevate privileges on the target system. Microsoft assigned this vulnerability a CVSS 3.1 base score of 8.8 with a scope change, reflecting the ability to compromise resources beyond the initially vulnerable component.

Critical Impact
A local, authenticated attacker can escalate to higher privileges by abusing file link resolution in Microsoft Edge Update, gaining full confidentiality, integrity, and availability impact on affected systems.

Affected Products

Microsoft Edge Update (Chromium-based)
Windows systems running Microsoft Edge with the Edge Update service installed
All Edge Update versions prior to the fix documented in the Microsoft advisory

Discovery Timeline

2025-05-22 - CVE-2025-47181 published to the National Vulnerability Database
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-47181

Vulnerability Analysis

The vulnerability resides in how Microsoft Edge Update resolves file paths before accessing them. Edge Update runs with elevated privileges to install browser updates and modify protected directories. When the service accesses files without properly validating whether the path is a symbolic link, junction, or hard link, an attacker can redirect operations to arbitrary targets.

This class of flaw, known as link following, enables a low-privileged local user to trick a privileged process into reading, writing, or overwriting files the user could not normally touch. The result is privilege escalation from a standard user to a higher integrity context.

Root Cause

The root cause is a missing or insufficient check for reparse points and symbolic links before file operations. Microsoft Edge Update opens or writes files based on paths that can be swapped by an unprivileged attacker between the time-of-check and the time-of-use. The service does not enforce that target files reside within trusted directories or that the paths have not been redirected via NTFS junctions or symlinks.

Attack Vector

Exploitation requires local access and low-level privileges on the target system. An attacker plants a crafted symbolic link or NTFS junction in a location that Edge Update will access during its operation. When the update service performs its privileged file operation, it follows the attacker-controlled link and acts on a file chosen by the attacker.

Successful exploitation typically produces arbitrary file write, arbitrary file delete, or arbitrary DACL modification as the SYSTEM or service account. No user interaction is required beyond triggering the Edge Update workflow. Refer to the Microsoft Security Update Guide for CVE-2025-47181 for vendor-supplied technical detail.

Detection Methods for CVE-2025-47181

Indicators of Compromise

Creation of symbolic links, hard links, or NTFS junctions in directories accessed by MicrosoftEdgeUpdate.exe or associated service binaries
Unexpected file writes or DACL changes in protected directories such as C:\Program Files (x86)\Microsoft\EdgeUpdate\ performed on behalf of a standard user
New or modified binaries in Edge Update install paths that do not match Microsoft-signed release artifacts

Detection Strategies

Monitor process activity from MicrosoftEdgeUpdate.exe and setup.exe under Edge Update for file operations targeting user-writable paths
Alert on reparse point creation by non-privileged processes in directories that Edge Update traverses
Correlate elevated file operations with preceding link-creation events from unprivileged sessions to identify TOCTOU exploitation patterns

Monitoring Recommendations

Enable Windows object access auditing for Edge Update directories and record symbolic link creation events
Ingest Sysmon Event ID 11 (FileCreate) and Event ID 1 (ProcessCreate) telemetry into a central SIEM for correlation
Track version deployment of Microsoft Edge Update across the fleet to identify hosts still running vulnerable builds

How to Mitigate CVE-2025-47181

Immediate Actions Required

Apply the Microsoft security update for CVE-2025-47181 referenced in the Microsoft Security Update Guide
Verify the installed version of Microsoft Edge Update on all Windows endpoints and confirm it matches the patched release
Restrict interactive local logon on high-value systems to reduce the pool of accounts that could stage exploitation

Patch Information

Microsoft published the fix through the standard Edge servicing channel. The patch is delivered automatically to systems with Microsoft Edge auto-update enabled. Administrators managing offline or restricted environments should consult the Microsoft advisory for the specific fixed version and manual deployment guidance.

Workarounds

Ensure Microsoft Edge auto-update is enabled so the fixed Edge Update component is deployed as soon as it becomes available
Limit local administrative and interactive access to endpoints, since exploitation requires an authorized local account
Audit and remove unauthorized symbolic links or junctions in directories used by Edge Update as a compensating control until patching completes

bash

# Verify installed Microsoft Edge Update version on Windows
reg query "HKLM\SOFTWARE\WOW6432Node\Microsoft\EdgeUpdate\Clients" /s

# Force an Edge update check to pull the patched Edge Update component
"C:\Program Files (x86)\Microsoft\EdgeUpdate\MicrosoftEdgeUpdate.exe" /ua /installsource scheduler