CVE-2026-0421
📋 TL;DR
A BIOS vulnerability in certain Lenovo ThinkPad models allows Secure Boot to be disabled even when configured as 'On' in User Mode. This affects L13 Gen 6, L13 Gen 6 2-in-1, L14 Gen 6, and L16 Gen 2 ThinkPads. Attackers could potentially bypass Secure Boot protections to load unauthorized software.
💻 Affected Systems
- Lenovo ThinkPad L13 Gen 6
- Lenovo ThinkPad L13 Gen 6 2-in-1
- Lenovo ThinkPad L14 Gen 6
- Lenovo ThinkPad L16 Gen 2
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Attackers disable Secure Boot and load malicious bootloaders or firmware, enabling persistent malware, data theft, or system compromise.
Likely Case
Local attackers with physical or administrative access bypass Secure Boot to install bootkits or modify system integrity.
If Mitigated
With proper physical security and administrative controls, risk is limited to authorized users exploiting the flaw.
🎯 Exploit Status
Exploitation requires BIOS access privileges; no public exploits known as per advisory.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: BIOS update as specified in Lenovo advisory LEN-210688
Vendor Advisory: https://support.lenovo.com/us/en/product_security/LEN-210688
Restart Required: Yes
Instructions:
1. Visit Lenovo support site. 2. Download latest BIOS update for your model. 3. Run update utility with admin privileges. 4. Restart system as prompted.
🔧 Temporary Workarounds
Switch to Setup Mode
allChange Secure Boot from User Mode to Setup Mode to avoid the vulnerability.
Restrict BIOS Access
allSet BIOS passwords and restrict physical access to prevent unauthorized changes.
🧯 If You Can't Patch
- Enforce strict physical security controls to prevent unauthorized BIOS access.
- Monitor systems for unexpected Secure Boot configuration changes or boot integrity alerts.
🔍 How to Verify
Check if Vulnerable:
Check BIOS version against patched versions in Lenovo advisory; verify Secure Boot is in User Mode.Check Version:
On Windows: wmic bios get smbiosbiosversion; On Linux: dmidecode -s bios-versionVerify Fix Applied:
Confirm BIOS version is updated per advisory and test Secure Boot remains enabled in User Mode.📡 Detection & Monitoring
Log Indicators:
- BIOS/UEFI event logs showing Secure Boot disabled unexpectedly
- System boot logs indicating unsigned bootloader execution
SIEM Query:
Event ID 12 from UEFI/BIOS logs OR boot integrity alerts from security tools