CVE-2025-29811
📋 TL;DR
This vulnerability allows an authorized attacker with local access to a Windows system to exploit improper input validation in the Mobile Broadband component, leading to privilege escalation. It affects Windows systems with Mobile Broadband functionality enabled. Attackers need valid credentials to initially access the system before exploiting this flaw.
💻 Affected Systems
- Windows Mobile Broadband
📦 What is this software?
Windows 11 22h2 by Microsoft
Windows 11 23h2 by Microsoft
Windows 11 24h2 by Microsoft
⚠️ Risk & Real-World Impact
Worst Case
An attacker with standard user credentials gains SYSTEM/administrator privileges, enabling complete system compromise, data theft, malware persistence, and lateral movement within the network.
Likely Case
Malicious insider or compromised user account elevates privileges to install additional malware, access sensitive data, or bypass security controls.
If Mitigated
With proper access controls, least privilege principles, and network segmentation, impact is limited to the local system with reduced lateral movement potential.
🎯 Exploit Status
Requires local access and authorized credentials. CWE-20 (Improper Input Validation) suggests exploitation involves crafting malicious input to trigger privilege escalation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Microsoft Security Update Guide for specific KB numbers
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-29811
Restart Required: Yes
Instructions:
1. Open Windows Update Settings
2. Click 'Check for updates'
3. Install all available security updates
4. Restart system when prompted
🔧 Temporary Workarounds
Disable Mobile Broadband
windowsRemove or disable Mobile Broadband functionality if not required
Disable via Device Manager: Right-click Mobile Broadband adapter → Disable device
Restrict Local Access
allImplement strict access controls to prevent unauthorized local access
🧯 If You Can't Patch
- Implement strict least privilege principles - ensure users don't have unnecessary local access
- Enable application control/whitelisting to prevent execution of unauthorized binaries
🔍 How to Verify
Check if Vulnerable:
Check Windows Update history for missing security patches related to CVE-2025-29811Check Version:
wmic os get caption, version, buildnumberVerify Fix Applied:
Verify the specific KB patch from Microsoft advisory is installed via 'Settings > Windows Update > Update history'📡 Detection & Monitoring
Log Indicators:
- Unusual privilege escalation events in Windows Security logs (Event ID 4672)
- Suspicious Mobile Broadband service activity
Network Indicators:
- Unusual outbound connections following local privilege escalation
SIEM Query:
EventID=4672 AND SubjectUserName!=SYSTEM AND NewProcessName contains suspicious patterns