Tor before 0.4.9.7 can attempt or accept BEGIN_DIR via conflux legs, aka TROVE-2026-008.
https://www.openwall.com/lists/oss-security/2026/05/06/8
https://gitlab.torproject.org/tpo/core/tor/-/work_items/41243
https://gitlab.torproject.org/tpo/core/tor/-/commit/50f90ba849088247734786922855c22661c6fa03
https://forum.torproject.org/c/news/tor-release-announcement/28