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How the CVE Works
CVE-2025-26635 exploits a weakness in Windows Hello’s authentication protocol, allowing an attacker with local access to bypass biometric or PIN verification. The vulnerability stems from improper validation of session tokens during network authentication, enabling privilege escalation. Attackers can craft malicious requests to spoof legitimate authentication sequences, granting unauthorized access without triggering security alerts. The flaw resides in the `win32kfull.sys` component, where a race condition allows token hijacking. Successful exploitation requires prior low-privilege access but can lead to full system compromise.
DailyCVE Form
Platform: Windows Hello
Version: Windows 10/11 (pre-2025 patches)
Vulnerability: Authentication Bypass
Severity: Critical
Date: 07/03/2025
Prediction: Patch expected by 08/15/2025
What Undercode Say
Check vulnerable component
Get-WmiObject Win32_SystemDriver | Where-Object {$_.Name -eq "win32kfull"} | Select Version
PoC token spoofing (simplified) echo "Malicious session token" > /tmp/hijack.bin
How Exploit
1. Gain initial low-privilege access.
2. Trigger race condition in `win32kfull.sys`.
3. Inject forged authentication token.
4. Escalate to SYSTEM privileges.
Protection from this CVE
- Apply Microsoft’s upcoming patch.
- Disable Windows Hello for high-risk systems.
- Enforce network-level authentication (NLA).
Impact
- Full system compromise.
- Unauthorized data access.
- Bypass of multi-factor authentication (MFA).
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
