Help with a debdiff for tigervnc

[Andrew C Aitchison]

Debian have fixed a security bug in tigervnc which is in universe,
so someone needs to generate a debdiff for the security team to
  review it and publish the package:
https://bugs.launchpad.net/ubuntu/+source/tigervnc/+bug/2048442

Debian have fixed this by building tigervnc 1.13.1 with xorg-server-source
> = 2:21.1.10, but Ubuntu 23.10 has tigervnc 1.12.0+dfsg-8 and
> xorg-server-source
2:21.1.7-3ubuntu2.6

On a good day I can build a .deb from source, but I am not familiar with
debdiffs and it is not clear to me that changing the upstream version
(either for mantic or noble) is a casual thing to do.

What is the next step to get this fix published ?

Thanks,

-- 
Andrew C. Aitchison                      Kendal, UK
                    andrew at aitchison.me.uk