Safely writing to /tmp/ was solved in 1986. Personally I would consider this class of bug the "idiot software developer" class (or to be more charitable: "security-illiterate software developer"). My evidence? There are (at least) six different OS primitives that will avoid this bug.
If you RTFA you'll read (under "What is the issue?")
> This file, /tmp/framer.txt, may be readable by other users on the remote host.
This is EXACTLY a non-safe writing to /tmp
Yes, there are safe ways to write to /tmp, as described in the systemd link I provided, but no, it is not safe to naively write to /tmp. Same issue as the "Many Perils of /tmp" link I provided.
A solution that no one uses is not a solution.
If you're gonna be arrogant, you better also be right.
https://salvatoresecurity.com/the-many-perils-of-tmp/
https://systemd.io/TEMPORARY_DIRECTORIES/