A hopefully-helpful diagram to help you determine a course of action about the liblzma thing.

readme.md

flowchart TD
    A[Should I update my system because of the liblzma thing?] --> B((Do you use a rolling release distro?<br>Think Arch Linux, Manjaro, nixos/nixpkgs-unstable, ....<br>Notably, this does not include stable-release distros like Ubuntu, unless you manually installed a newer version of the affected software.))  
    B --> C[Yes] --> D(Have you updated within the last two to three weeks?)
    D --> O[Yes]
    D --> P[No] --> K
    O --> E[Run the script attached below. Did it come back positive?] --> F(Yes)
    F --> G[Update now.]
    E --> H[No]
    H --> I[Consider updating either way.]
    B --> J[No] --> K[You don't need to update because of this.]
    J --> W[I don't trust you.] --> E

Loading

detection_script.sh

#!/usr/bin/env bash

set -eu

# find path to liblzma used by sshd
path="$(ldd $(which sshd) | grep liblzma | grep -o '/[^ ]*')"

# does it even exist?
if [ -z "$path" ]
then
	echo probably not vulnerable
	exit
fi

# check for function signature
if hexdump -ve '1/1 "%.2x"' "$path" | grep -q f30f1efa554889f54c89ce5389fb81e7000000804883ec28488954241848894c2410
then
	echo probably vulnerable
else
	echo probably not vulnerable
fi