After upgrading from Zabbix 4.0.25 to Zabbix 4.0.26 the net.ssh items go into an unsupported state due to "Cannot read data from SSH server".

With the upgrade to Zabbix 4.0.26 the libssh-4 (0.8.7-1+deb10u1) library looks like a new dependancy and is also installed.

System:

• OS: Debian 10
• Zabbix server

zabbix_server -V

zabbix_server (Zabbix) 4.0.26
Revision eb5a408168 26 October 2020, compilation time: Oct 21 2020 16:24:53

Compiled with OpenSSL 1.1.1d 10 Sep 2019
Running with OpenSSL 1.1.1d 10 Sep 2019

Debug logs:

{{ 1603:20201106:081018.042 In substitute_key_macros() data:'ssh.run[DiskSpace,10.0.0.136,22,]'}}
{{ 1603:20201106:081018.042 End of substitute_key_macros():SUCCEED data:'ssh.run[DiskSpace,10.0.0.136,22,]'}}
{{ 1603:20201106:081018.042 In get_value() key:'ssh.run[DiskSpace,10.0.0.136,22,]'}}
{{ 1603:20201106:081018.204 Item [test_node1:ssh.run[DiskSpace,10.0.0.136,22,]] error: Cannot read data from SSH server}}
{{}}

On Zabbix version 4.0.25 the exact same check works 100%.