Ubuntu still ships 5.4.5 on 24.03 (atm).

I did a quick diff of the source (.orig file from packages.ubuntu.com) and the content mostly matched the 5.4.5 github tag except for Changelog and some translation files. It does match the tarball content, though.

So for 5.4.5 the tagged release and download on github differ.

It does change format strings, e.g.

   +#: src/xz/args.c:735
   +#, fuzzy
   +#| msgid "%s: With --format=raw, --suffix=.SUF is required unless writing to stdout"
   +msgid "With --format=raw, --suffix=.SUF is required unless writing to stdout"
   +msgstr "%s: amb --format=raw, --suffix=.SUF és necessari si no s'escriu a la sortida estàndard"

There is no second argument to that printf for example. I think there is at least a format string injection in the older tarballs.

[Edit] formatting