Nintendo Switch 2 Software-Only Jailbreak Released Using SmileBASIC 4

A security researcher has released a software-only jailbreak for Nintendo Switch 2 that allows native code execution without requiring a hardware modchip. The exploit, called ns2jb, works on firmware version 23.0.1, although it does not currently support permanent custom firmware.

Developed by Sammy Hajhamid, also known as pepsipu, the jailbreak uses vulnerabilities in the Nintendo Switch programming application SmileBASIC 4 and the console's filesystem service. Hajhamid has published the exploit alongside a technical breakdown and footage showing unofficial characters running in Mario Kart World.

The jailbreak begins with SmileBASIC 4, a programming application originally released for Nintendo Switch in 2020. The software also runs on Switch 2 through backward compatibility, allowing Hajhamid to target vulnerabilities in the older application.

Using OpenAI's Codex, the researcher discovered an integer overflow in the application's BASIC interpreter. A separate vulnerability in the Switch 2's filesystem service then allowed greater system access, eventually making it possible to execute custom native code with the permissions of certain system processes.

Hajhamid said the jailbreak took approximately two weeks of substantial work. Codex assisted with vulnerability research and developing parts of the exploit, but the researcher clarified that the process involved considerably more than simply instructing AI to jailbreak the console.

To demonstrate what the exploit could achieve, Hajhamid modified Mario Kart World to include characters such as Cinnamoroll, Peter Griffin, and Hatsune Miku. Gameplay footage shows the unofficial additions appearing in Nintendo's Switch 2-exclusive racing game.

The researcher says ns2jb could also support homebrew applications, game modding, reverse engineering, and save file backups. These capabilities provide a starting point for developers interested in exploring the console beyond Nintendo's official software restrictions.

However, the publicly released package remains a limited proof of concept. It demonstrates native code execution inside the Switch 2's filesystem service rather than providing a complete collection of homebrew tools.

Despite being software-only, ns2jb is a tethered jailbreak. Its current public demonstration requires SmileBASIC 4 version 4.4.9 and a computer running macOS or Linux, with both devices connected to the same network.

The exploit does not install permanent custom firmware. Restarting the console removes its modifications, and the process must be performed again to regain access. The researcher also confirmed that the current method does not provide control over every built-in system process.

Nintendo lists firmware 23.0.1 as the latest Switch 2 system update, while the exploit's public documentation confirms testing on that version.

Following the exploit's publication, SmileBASIC 4 became difficult to find or purchase through Nintendo's digital storefront in several regions. Nintendo's US product link currently returns an error, although official listings remain accessible in some other regions.

Nintendo has not publicly acknowledged ns2jb or confirmed whether the apparent storefront changes are connected to the jailbreak. There has also been no official announcement of a worldwide removal.

Hajhamid hopes the discovery will encourage further Switch 2 homebrew development. The researcher has suggested adapting the filesystem exploit to a browser-based entry point and investigating ways to gain access to other built-in system processes. Neither capability is included in the current public release.