Ubuntu 26.04 LTS – Secure Boot blocks third-party kernel module loading

📖 ~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

Administrators observe: Ubuntu 26.04 LTS – Secure Boot blocks third-party kernel module loading. Hardware acceleration or device drivers fail to initialize.

Environment & Reproduction

Issue appears with DKMS modules after kernel upgrades on Secure Boot enabled systems.

# Baseline context
lsb_release -a
mokutil --sb-state
uname -r
dkms status
sudo journalctl -k -n 120 --no-pager

Root Cause Analysis

Unsigned or un-enrolled module keys cause kernel to reject module insertion under Secure Boot policy.

Quick Triage

Check dmesg for signature enforcement messages and module state.

# Quick triage
dmesg | grep -Ei 'secure boot|signature|module verification' | tail -n 60
lsmod | head
modinfo  | grep -Ei 'sign|sig' || true

Step-by-Step Diagnosis

Validate MOK enrollment and DKMS build status for the target module.

# Detailed diagnosis
mokutil --list-enrolled | head -n 80
dkms status
sudo tail -n 120 /var/lib/dkms/*/*/build/make.log 2>/dev/null || true

Solution – Primary Fix

Rebuild module, sign with enrolled key, and load module.

# Primary fix
sudo dkms autoinstall
# Sign module if required by your environment
sudo modprobe 
lsmod | grep 

Solution – Alternative Approaches

Temporarily disable Secure Boot in firmware only for emergency recovery windows.

# Alternative
# Disable Secure Boot in firmware setup, then reboot
sudo modprobe 

Verification & Acceptance Criteria

Target module loads successfully and corresponding hardware functionality is restored.

# Verify
lsmod | grep 
dmesg | tail -n 80
mokutil --sb-state

Rollback Plan

Unload problematic module and revert to previous signed driver package.

# Rollback
sudo modprobe -r 
sudo apt-get install --reinstall -y 

Prevention & Hardening

Include module signing and MOK verification in kernel update runbooks.

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# Hardening
dkms status
mokutil --list-enrolled | wc -l
sudo journalctl -k --since '7 days ago' --no-pager | grep -Ei 'verification|secure boot' || true

Related Errors & Cross-Refs

Related patterns include module verification failed: signature and/or required key missing.

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 DKMS integration documentation.