CVE-2025-9201: Lenovo Browser DLL Hijacking Vulnerability

CVE-2025-9201 Overview

CVE-2025-9201 is a DLL hijacking vulnerability in Lenovo Browser identified during an internal security assessment. The flaw allows a local, authenticated user to load an attacker-controlled Dynamic Link Library (DLL) and execute code with elevated privileges. The issue is tracked under CWE-427: Uncontrolled Search Path Element.

Lenovo published the finding through its internal advisory portal. No public exploit code, proof-of-concept, or evidence of exploitation in the wild has been reported. The vulnerability requires local access and low privileges, but successful exploitation compromises confidentiality, integrity, and availability of the affected host.

Critical Impact
A local user can place a malicious DLL in a path searched by Lenovo Browser and gain code execution at elevated privileges.

Affected Products

Lenovo Browser (Windows)
Refer to the Lenovo Security Advisory for specific affected versions
Systems where Lenovo Browser is installed with elevated service or update components

Discovery Timeline

2025-09-11 - CVE-2025-9201 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-9201

Vulnerability Analysis

CVE-2025-9201 is a DLL hijacking issue rooted in an uncontrolled search path used by Lenovo Browser when loading libraries at runtime. Windows applications that call LoadLibrary without a fully qualified path fall back to the standard DLL search order. If a writable directory precedes the intended system path, an attacker-supplied DLL is loaded in place of the legitimate one.

Because the affected browser component runs with elevated privileges during specific operations, such as update or installation flows, the hijacked DLL inherits those privileges. This converts a low-privilege local user into an administrative code execution primitive on the host.

Root Cause

The root cause is improper resolution of DLL search paths within Lenovo Browser [CWE-427]. The application does not enforce absolute paths, safe search mode, or signature verification for its dependent libraries. An attacker who can write to a directory in the search order can plant a rogue DLL that matches the name of a legitimate dependency.

Attack Vector

Exploitation requires local access with low privileges. The attacker places a crafted DLL in a directory that Lenovo Browser searches before the intended system location. When the browser or its associated privileged component loads the library, the malicious code runs in the context of that process.

Typical staging locations include the application's install directory, per-user temporary paths, or directories inherited through environment variables such as PATH. See the Lenovo Security Advisory for vendor-specific technical details.

Detection Methods for CVE-2025-9201

Indicators of Compromise

Unexpected DLL files in Lenovo Browser install directories or user-writable subdirectories
Lenovo Browser processes loading modules from non-standard paths such as %TEMP%, %APPDATA%, or user profile directories
Child processes spawned by Lenovo Browser components running with elevated tokens
Recently modified DLLs in application folders that do not carry a valid Lenovo digital signature

Detection Strategies

Monitor ImageLoad events for Lenovo Browser executables and flag DLLs loaded from writable or non-standard directories
Alert on unsigned or improperly signed DLLs loaded by Lenovo Browser processes
Track file creation events for .dll files within Lenovo Browser install paths by non-installer processes
Correlate privilege escalation attempts with Lenovo Browser update or launch activity

Monitoring Recommendations

Enable Sysmon Event ID 7 (ImageLoad) with filters targeting Lenovo Browser process names
Baseline the legitimate DLL inventory shipped with Lenovo Browser and alert on deviations
Audit write access to Lenovo Browser installation directories and restrict where feasible
Log elevation events tied to Lenovo Browser child processes for forensic review

How to Mitigate CVE-2025-9201

Immediate Actions Required

Apply the fixed version of Lenovo Browser as documented in the Lenovo Security Advisory
Restrict write permissions on Lenovo Browser installation directories to administrators only
Remove Lenovo Browser from systems where it is not required for business operations
Audit endpoints for existing unauthorized DLLs in Lenovo Browser paths

Patch Information

Lenovo has published a security advisory for CVE-2025-9201. Administrators should consult the Lenovo Security Advisory for the fixed build number and update instructions. Deploy the update through managed software distribution to ensure consistent remediation across the fleet.

Workarounds

Remove non-administrator write permissions from the Lenovo Browser install directory and its subfolders
Enforce application allowlisting to block execution of unsigned DLLs loaded by Lenovo Browser
Uninstall Lenovo Browser on endpoints where it is not actively used until the patch is applied
Monitor for unexpected DLL creation events in Lenovo Browser paths and quarantine suspicious files

bash

# Configuration example: restrict write access on the Lenovo Browser install directory (Windows)
icacls "C:\Program Files\Lenovo\LenovoBrowser" /inheritance:r
icacls "C:\Program Files\Lenovo\LenovoBrowser" /grant:r "Administrators:(OI)(CI)F" "SYSTEM:(OI)(CI)F" "Users:(OI)(CI)RX"