CVE-2025-66676: IObit Unlocker DoS Vulnerability

CVE-2025-66676 Overview

A Denial of Service (DoS) vulnerability has been identified in IObit Unlocker version 1.3.0.11. This vulnerability allows attackers to cause a system disruption via a crafted request, potentially rendering the application unresponsive and impacting system stability.

Critical Impact

Local attackers can exploit this vulnerability to cause a Denial of Service condition, disrupting normal operations and potentially affecting system availability for users relying on IObit Unlocker functionality.

Affected Products

• IObit Unlocker v1.3.0.11

Discovery Timeline

• February 13, 2026 - CVE-2025-66676 published to NVD
• February 13, 2026 - Last updated in NVD database

Technical Details for CVE-2025-66676

Vulnerability Analysis

This vulnerability is classified under CWE-400 (Uncontrolled Resource Consumption), indicating that the application fails to properly limit resource allocation when processing certain requests. The flaw requires local access to exploit, meaning an attacker must have some level of access to the target system. No user interaction is required to trigger the vulnerability, and successful exploitation results in high impact to system availability while confidentiality and integrity remain unaffected.

The vulnerability exists within IObit Unlocker, a Windows utility designed to help users delete stubborn files that cannot be removed through normal means. The tool operates with elevated privileges to unlock files held by system processes, which makes resource exhaustion vulnerabilities particularly concerning in this context.

Root Cause

The root cause is related to CWE-400: Uncontrolled Resource Consumption. IObit Unlocker v1.3.0.11 does not properly validate or limit resources when handling certain crafted requests. This allows an attacker to trigger excessive resource consumption, leading to application hang or crash. The lack of proper input validation and resource management controls enables the denial of service condition.

Attack Vector

The attack vector is local, requiring the attacker to have access to the system where IObit Unlocker is installed. By sending a specially crafted request to the application, an attacker can trigger uncontrolled resource consumption. This could be accomplished through malicious input files, specially formatted unlock requests, or by exploiting the application's IPC mechanisms.

Technical details and a proof-of-concept demonstrating the exploitation method are available in the GitHub PoC Repository. Security researchers should review this resource for specific exploitation mechanics.

Detection Methods for CVE-2025-66676

Indicators of Compromise

• Unexpected crashes or hangs of the IObitUnlocker.exe process
• Abnormal resource consumption (CPU or memory spikes) associated with IObit Unlocker
• System event logs showing application errors related to IObit Unlocker
• Presence of unusual or malformed files being processed by the unlocker utility

Detection Strategies

• Monitor process behavior for IObitUnlocker.exe using endpoint detection tools to identify abnormal resource usage patterns
• Implement application whitelisting to control which users and processes can interact with IObit Unlocker
• Deploy file integrity monitoring to detect suspicious files that may be crafted to exploit the vulnerability
• Configure endpoint protection to alert on repeated application crashes or resource exhaustion events

Monitoring Recommendations

• Enable detailed logging for application crashes and resource consumption anomalies
• Set up alerts for high CPU or memory usage associated with IObit Unlocker processes
• Monitor system stability metrics on endpoints where IObit Unlocker is deployed
• Track user activity involving file unlock operations for unusual patterns

How to Mitigate CVE-2025-66676

Immediate Actions Required

• Restrict access to IObit Unlocker to only authorized administrators who require the functionality
• Consider temporarily uninstalling or disabling IObit Unlocker until a patch is available
• Implement application control policies to limit execution of IObitUnlocker.exe
• Review and audit systems where IObit Unlocker is installed to assess exposure

Patch Information

No vendor patch information is currently available in the CVE data. Users should monitor the IObit Unlocker Tool Page for security updates and newer versions that may address this vulnerability. Consider upgrading to a newer version if one becomes available that resolves this issue.

Workarounds

• Limit local user access to systems where IObit Unlocker is installed
• Use alternative file unlocking methods or tools that are not affected by this vulnerability
• Implement strict access controls and least-privilege principles for workstations
• Consider running IObit Unlocker in an isolated environment if its use is essential

# Example: Restrict execution of IObit Unlocker using Windows AppLocker
# Create a deny rule for non-administrator users
# Open Group Policy Editor and navigate to:
# Computer Configuration > Windows Settings > Security Settings > Application Control Policies > AppLocker

# PowerShell command to check if IObit Unlocker is installed
Get-ItemProperty "HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\*" | Where-Object { $_.DisplayName -like "*IObit Unlocker*" }