Care to share it? Still trying to convince my provider to go this route...
But since one of the main ways this vulnerability can be triggered (by causing out of memory) involves multipart POSTs, I have found it useful to stop multipart POSTs ever reaching the vulnerable application, which you can do in an Nginx proxy.
It is only buying me time, but unfortunately time is what I need, since my application must keep running, but cannot be run on any supported release.
Besides that, also with Mythos I managed to build PHP 5.6.40 for Jessie (Don't ask) but that's an entire different story (we ended up force upgrading to Bookworm, and there's a huge silver lining for us with that anyway)