Cloudron down after Ubuntu/Docker update (Docker service fails to start)

[Valexico]

Hi @james
So what should we do at the end? My cloudron server is quite critical for my business, and deleting a config file to make it up sounds a bit scary. I would be glad to have an official fix or recommendation on this.

[james]

Hello @valexico
Can you please write a mail to support@cloudron.io and enable remote support?
Also, please give us a timeframe when we can restart processes like the docker and the box service to analyse the issue.

[joseph]

Thanks for the access @valexico . The issue has to do with the faulty ubuntu kernel update . Updating the firewall makes it work.

Technical details: Cloudron configures docker and containers to log using the syslog service (cloudron-syslog) . Because of the kernel regression, docker is unable to reach the syslog service and doesn't start anymore. The cgroupfs was not the issue.

We are making a patch release for Cloudron which fixes the firewall rules .

[Valexico]

@joseph
At the end is it related to hostinger config or any user would face this issue upon reboot ? Where does the faulty update comes from ?

[joseph]

@valexico issue is not specific to hostinger . Ubuntu has pushed a new kernel which is causing problems with Cloudron's firewall. We are making a new release to workaround this issue.

[AndyCPNW]

Just experienced this today. Also on Hostinger. Requested reboot and system will not come back online. Have not applied the fix yet so if you want a system that is still broken and you want to investigate, let me know.

[joseph]

@AndyCPNW please check the ubuntu kernel versions. It's 110 probably?

The quick fix:

• Edit /etc/systemd/system/docker.service.d/cloudron.conf . Change --log-driver=json-file .
• systemctl daemon-reload and systemctl restart docker box

Cloudron 9.1.7 is being rolled out. You can update once the system is up and it will fix the firewall.

[AndyCPNW]

@joseph Thanks - I tried the cloudron-firewall.sh patch and restarting but did not get docker to come up so I deleted the conf file like the original solution suggested and it came right back again. Yes it was kernel 110. Everything seems to be running now. Bummer that kernel upgrade caused all of this. Thanks for the help.

[phil_b]

Hello,

I am experiencing the same issue, which appeared suddenly. I have tried the different fixes suggested in this thread, but none of them really worked.

Last night, I was able to restart the server and everything seemed to be working fine. However, this morning when I checked again, the system was unresponsive once more.

I am currently traveling for the next 10 days, away from my office, and I only have an iPad with me. I connect to a computer at my office remotely, and from there I access my Cloudron. However, the internet connection where I am is very unstable, which makes troubleshooting extremely difficult.

Thank you in advance for any help you can provide.

Best regards,
Philippe

[nebulon]

This was fixed in support. The system had a file /etc/docker/daemon.json which also specified the log-driver causing docker to refuse to start. Simple removing that file and restarting docker brought the system back.

[phil_b]

@nebulon Thank you so much. It's work now.

[ntnsndr]

Greetings, all. My server is upgraded to 9.1.7 on Hostinger. I woke up to find that it was down; perhaps this occurred during the automatic upgrade. There was an error on the dashboard:

Platform startup failed
Failed to start services. Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

I saw @nebulon's last post and removed the daemon.json file. Then restarted the server. It was a longer than usual reboot process, especially hanging for a few minutes on restarting Redis. But eventually all the apps got up and running.

Should I be concerned that this might happen again? Or should it be smoother from now on?

[james]

Hello @ntnsndr

@ntnsndr said:

Should I be concerned that this might happen again? Or should it be smoother from now on?

Should be good now.

[osobo]

Hello everyone. Glad the issue is now fixed.

FYI I've received yesterday a legit notification from Hostinger mentioning the following:

**Linux kernel vulnerability disclosed (CVE-2026-31431)**

A security flaw called "Copy Fail" (CVE-2026-31431) has been found in the Linux kernel. It affects nearly all major Linux distributions – including Ubuntu, Debian, RHEL, Amazon Linux, SUSE, Fedora, and more – on any kernel built between 2017 and today.

The vulnerability lets a local user gain full admin access to a server. It can also affect containerized environments.

The fix takes just a few minutes.

Option 1: Update your kernel (recommended)

For Ubuntu/Debian: sudo apt update, sudo apt upgrade -y
For RHEL-based systems: sudo yum update
Then reboot your server.

Option 2: Disable the affected module (temporary fix)

If updating right now isn't an option, disable the vulnerable module to reduce exposure:

echo "install algif_aead /bin/false" > /etc/modprobe.d/disable-algif.conf rmmod algif_aead 2>/dev/null || true

This won't affect SSH, TLS, LUKS, or OpenSSL."

I'm wondering. Is this issue already addressed by Cloudron's latest updates or should I apply the fix myself ?

Thanks for your support and happy workers' Day

[james]

Hello @osobo
This should be taken care of by the unattended updates automatically.
Just make sure that you restart you Cloudron server when it tells you to do so in the dashboard notifications.

[osobo]

Thank you @james . Well noted. Best regards