In UNIX Fourth Research Edition (v4), the su command is vulnerable to a buffer overflow due to the 'password' variable having a fixed size of 100 bytes. A local user can exploit this to gain root privileges. It is unlikely that UNIX v4 is running anywhere outside of a very small number of lab environments. NOTE: This vulnerability only affects products that are no longer supported by the maintainer.
https://www.tuhs.org/pipermail/tuhs/2026-January/032991.html
https://www.spinellis.gr/blog/20251223/
https://sigma-star.at/blog/2025/12/unix-v4-buffer-overflow/
https://discuss.systems/@ricci/115747843169814700