tl;dr: ns2jb is the first software-only tethered jailbreak for the Switch 2 (firmware 23.0.1), achieving arbitrary native code execution as any ordinary sysmodule and the built-in fs sysmodule. The author bypassed WebKit's mitigations (PAC, CFI, XOM) by instead exploiting an integer overflow in the Switch 1 game SmileBASIC for initial ROP, then used a path-normalization buffer overflow in fs to gain arbitrary R/W, and finally abused the loader's signature-check flow to run arbitrary code under any sysmodule's permissions. Codex (AI) assisted with exploit development, and a Mario Kart World mod was built as a demo.