Ubuntu 26.04 LTS – Secure Boot blocks third-party kernel module – Fix & Prevention

📖 ~1 min read

Table of contents

1. Symptom & Impact
2. Environment & Reproduction
3. Root Cause Analysis
4. Quick Triage
5. Step-by-Step Diagnosis
6. Solution – Primary Fix
7. Solution – Alternative Approaches
8. Verification & Acceptance Criteria
9. Rollback Plan
10. Prevention & Hardening
11. Related Errors & Cross-Refs
12. References & Further Reading

Symptom & Impact

Required device or security software fails because unsigned module is not loaded.

Environment & Reproduction

Seen on systems with Secure Boot enabled using DKMS or vendor modules.

mokutil --sb-state

Root Cause Analysis

Kernel enforces signature validation and rejects modules not signed with enrolled keys.

Quick Triage

Confirm Secure Boot state and check kernel module load logs.

mokutil --sb-state
journalctl -k | grep -i 'module verification'

Step-by-Step Diagnosis

Identify blocked module and verify its signature metadata.

modinfo  | grep -Ei 'signer|sig'
lsmod | grep 

Solution – Primary Fix

Sign module with enrolled key or enroll a Machine Owner Key and rebuild module.

sudo update-secureboot-policy --enroll-key
sudo dkms autoinstall

Solution – Alternative Approaches

Disable Secure Boot only if security policy explicitly permits that exception.

Verification & Acceptance Criteria

Module loads without verification errors and dependent service functions normally.

sudo modprobe 
lsmod | grep 

Rollback Plan

Remove new key enrollment and return to known-good signed module package.

Prevention & Hardening

Standardize signed module pipeline for all DKMS-based components.

Related Errors & Cross-Refs

Related to NVIDIA module load issues and virtual device driver failures.

Related tutorial: View the step-by-step tutorial for Ubuntu 26.04 LTS.

View all Ubuntu 26.04 LTS tutorials on the Tutorials Hub →

Browse all common problems & solutions on the Tutorials Hub.

References & Further Reading

Ubuntu Secure Boot and module signing documentation.