I know this is an old post, but looks like Sophos has ignored updating OpenSSL in the firmware.
UTM 9.407003 -
>openssl version
OpenSSL 1.0.1k 8 Jan 2015
Client download however is: library versions: OpenSSL 1.0.1t 3 May 2016, LZO 2.09
Since there have been numerous firmware updates, why has Sophos ignored updating OpenSSL to a later version?
This type of question has been asked and answered regularly here. Originally Astaro Security Linux, the UTM runs in a hardened version of Suse Linux. No new version of one of the components is added until it's been thoroughly tested. Unless there's a compelling reason to make that effort, it's usually easier/surer to patch the version currently in use.
What specific vulnerability concerns you that existed in "k" but has been resolved in the "t" version?
Cheers - Bob