CVE-2025-63945: Tencent iOA Privilege Escalation Flaw

CVE-2025-63945 Overview

CVE-2025-63945 is a privilege escalation vulnerability affecting the Tencent iOA (intelligent Office Appliance) application on Windows devices. This security flaw enables a local user to execute programs with elevated privileges by exploiting a race condition within the application. The vulnerability is classified under CWE-59 (Improper Link Resolution Before File Access), commonly known as a symlink attack vulnerability.

Critical Impact

Local attackers can escalate privileges to execute arbitrary programs with elevated permissions, potentially gaining full system control on affected Windows endpoints running Tencent iOA through version 210.9.28693.621001.

Affected Products

• Tencent iOA through version 210.9.28693.621001 on Windows

Discovery Timeline

• 2026-02-23 - CVE-2025-63945 published to NVD
• 2026-02-26 - Last updated in NVD database

Technical Details for CVE-2025-63945

Vulnerability Analysis

This privilege escalation vulnerability in Tencent iOA stems from improper handling of file operations that can be exploited through a race condition. The vulnerability requires local access to the target system, meaning an attacker must already have some level of access to the Windows device running the vulnerable iOA application.

The attack requires successfully winning a race condition, which involves timing-sensitive operations where an attacker must manipulate the system state between the time a check is performed and the time an action is taken. While this increases the complexity of exploitation, determined attackers with local access can repeatedly attempt the exploit until successful.

Successful exploitation allows a local user to execute programs with elevated privileges, potentially bypassing security controls and gaining administrative access to the affected system. This could enable further compromise including data exfiltration, malware installation, or lateral movement within an enterprise environment.

Root Cause

The root cause of CVE-2025-63945 is classified under CWE-59 (Improper Link Resolution Before File Access). This weakness occurs when the application follows symbolic links without properly verifying the target, allowing an attacker to redirect file operations to unintended locations. In this case, the Tencent iOA application fails to properly validate file paths before performing privileged operations, enabling attackers to exploit the timing window in file access operations.

Attack Vector

The attack vector for this vulnerability is local, requiring the attacker to have access to the target system. The exploitation process involves:

1. An attacker with local access identifies the privileged file operation performed by Tencent iOA
2. The attacker creates a symbolic link targeting a file they wish to manipulate
3. By exploiting the race condition between file check and file access operations, the attacker redirects the privileged operation
4. Upon successful timing of the race condition, the attacker's code executes with elevated privileges

Technical details and proof-of-concept information are available through the GitHub PoC repository for CVE-2025-63945.

Detection Methods for CVE-2025-63945

Indicators of Compromise

• Unusual symbolic link creation in directories associated with Tencent iOA installation
• Unexpected process spawning from Tencent iOA with elevated privileges
• Repeated file access operations targeting iOA application directories indicating race condition exploitation attempts
• Suspicious junction point or directory symbolic link modifications in system directories

Detection Strategies

• Monitor for symbolic link creation events in Tencent iOA installation directories using Windows file system auditing
• Implement endpoint detection rules to identify rapid, repeated file operations that may indicate race condition exploitation
• Deploy behavioral analytics to detect processes spawning with unexpected privilege levels from the iOA application
• Configure SIEM rules to correlate file system events with privilege escalation indicators

Monitoring Recommendations

• Enable detailed file system auditing on endpoints running Tencent iOA
• Monitor process creation events for child processes of iOA components running with SYSTEM privileges
• Implement real-time alerting for symbolic link creation in sensitive directories
• Review security logs for patterns consistent with TOCTOU (Time-of-Check to Time-of-Use) attack attempts

How to Mitigate CVE-2025-63945

Immediate Actions Required

• Identify all Windows endpoints running Tencent iOA version 210.9.28693.621001 or earlier
• Restrict local user access on systems where Tencent iOA is installed to minimize the attack surface
• Apply the principle of least privilege to limit potential impact of successful exploitation
• Monitor affected systems for indicators of compromise until patches are applied

Patch Information

Organizations should check with Tencent for security updates addressing this vulnerability. Monitor the Tencent iOA GitHub repository and official Tencent security channels for patch announcements and updated versions that remediate CVE-2025-63945.

Workarounds

• Limit local access to systems running Tencent iOA to trusted users only
• Implement application whitelisting to prevent unauthorized executables from running even if privilege escalation succeeds
• Consider temporarily disabling or restricting Tencent iOA functionality on critical systems until a patch is available
• Enable Windows Exploit Guard and other endpoint protection features to add defense-in-depth layers

# Example: Enable Windows file system auditing for Tencent iOA directories
auditpol /set /subcategory:"File System" /success:enable /failure:enable

# Monitor symbolic link creation using PowerShell
Get-WinEvent -FilterHashtable @{LogName='Security';Id=4663} | Where-Object {$_.Message -match "iOA"}