SSH addon missing KexAlgorithms

[bmfkai]

Describe the issue you are experiencing

Not entirely sure this would be considered a bug but I'm trying to connect to HA via the SSH addon and Solid Explorer. The issue I've come across with other ssh servers and connecting through Solid Explorer is that with the latest update to 10, diffie-hellman* appears to have been dropped from native support.

I've been able to correct this issue by re-adding support by adding this line to to /etc/ssh/sshd_config:
KexAlgorithms +diffie-hellman-group1-sha1,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1,diffie-hellman-group-exchange-sha256

I tried adding this to the SSH addon yaml with:
extra_args: "-o KexAlgorithms=+diffie-hellman-group1-sha1,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1,diffie-hellman-group-exchange-sha256"
but once the addon restarts, it removes this customization.

What type of installation are you running?

Home Assistant OS

Which operating system are you running on?

Home Assistant Operating System

Which add-on are you reporting an issue with?

Terminal & SSH

What is the version of the add-on?

9.20.1

Steps to reproduce the issue

1. add extra_args: "-o KexAlgorithms=+diffie-hellman-group1-sha1,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1,diffie-hellman-group-exchange-sha256" to the config yaml and restart the addon.
   2.--or-- add KexAlgorithms +diffie-hellman-group1-sha1,diffie-hellman-group14-sha1,diffie-hellman-group-exchange-sha1,diffie-hellman-group-exchange-sha256 to /etc/ssh/sshd_config and restart the addon.

System Health information

none

Anything in the Supervisor logs that might be useful for us?

2025-10-29 00:24:37.692 WARNING (MainThread) [supervisor.addons.options] Option 'extra_args' does not exist in the schema for Terminal & SSH (core_ssh)
2025-10-29 00:24:39.140 INFO (SyncWorker_15) [supervisor.docker.manager] Stopping addon_core_ssh application
2025-10-29 00:24:42.376 INFO (SyncWorker_15) [supervisor.docker.manager] Cleaning addon_core_ssh application
2025-10-29 00:24:42.603 INFO (MainThread) [supervisor.docker.addon] Starting Docker add-on homeassistant/amd64-addon-ssh with version 9.20.1

Anything in the add-on logs that might be useful for us?

Unable to negotiate with ##.##.##.## port 44222: no matching key exchange method found. Their offer: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group14-sha256,diffie-hellman-group1-sha1 [preauth]

Additional information

No response

[github-actions]

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