I find it a little bit concerning that the release note of V18.00 beta does not mention any fix for a security issues. I guess it's included in the "bug fixes"...
Yes, 18.00 beta is the patched version. The current release (non-beta) version is not patched yet. Moreover, the POSIX port of p7zip is not patched yet at all.
https://sourceforge.net/p/sevenzip/discussion/45797/thread/6...