A user on X (formerly Twitter) has posted claims that they have temporarily modded Mario Kart World on the Nintendo Switch 2 by taking advantage of an exploit in SmileBASIC, the homebrew-style development environment available on the Nintendo eShop.
The report outlines a multi-step process that the poster says allowed custom characters to appear in-game.
According to the X user, the modification placed non-official characters such as Cinnamoroll, Peter Griffin and Hatsune Miku into Mario Kart World — additions that would not be possible through standard consumer-facing game tools.
The poster described the workflow as complex, requiring ownership of SmileBASIC (version 4.4.9), a save file with over 20 MiB of data, console system software 23.0.1, and a local machine running Node.js 22 or later on macOS or Linux on the same network as the console.
The user also said the technique was discovered with assistance from OpenAI tools.
The claimant further noted that the reported access is not persistent: the process must be repeated after the console is powered off, and it does not amount to a permanent jailbreak or always-on custom firmware.
Those details, as presented by the user, suggest the exploit offers temporary code execution rather than long-term system compromise.
Context and history are important.
The original Nintendo Switch was widely compromised early in its lifecycle by a hardware-level bootrom exploit (commonly known in the scene as Fusée Gelée), which enabled persistent custom firmware and, in many cases, piracy.
Nintendo responded over time with firmware updates and legal measures.
The company has regularly issued system software updates to address security issues on its platforms.
At the time of writing, the claims posted to X remain user-reported details and have not been independently verified by Nintendo or the broader security research community.
The poster's step-by-step requirements and the temporary nature of access are factual descriptions of the claim as made public.
Historically, Nintendo has released software updates to patch verified vulnerabilities, and the industry typically monitors such reports closely.
We will continue to follow this story for confirmation from independent researchers or official statements from Nintendo.
For related coverage on Switch hardware, eShop releases and Nintendo news, check our Nintendo Switch hub.
The report outlines a multi-step process that the poster says allowed custom characters to appear in-game.
According to the X user, the modification placed non-official characters such as Cinnamoroll, Peter Griffin and Hatsune Miku into Mario Kart World — additions that would not be possible through standard consumer-facing game tools.
The poster described the workflow as complex, requiring ownership of SmileBASIC (version 4.4.9), a save file with over 20 MiB of data, console system software 23.0.1, and a local machine running Node.js 22 or later on macOS or Linux on the same network as the console.
The user also said the technique was discovered with assistance from OpenAI tools.
The claimant further noted that the reported access is not persistent: the process must be repeated after the console is powered off, and it does not amount to a permanent jailbreak or always-on custom firmware.
Those details, as presented by the user, suggest the exploit offers temporary code execution rather than long-term system compromise.
Context and history are important.
The original Nintendo Switch was widely compromised early in its lifecycle by a hardware-level bootrom exploit (commonly known in the scene as Fusée Gelée), which enabled persistent custom firmware and, in many cases, piracy.
Nintendo responded over time with firmware updates and legal measures.
The company has regularly issued system software updates to address security issues on its platforms.
At the time of writing, the claims posted to X remain user-reported details and have not been independently verified by Nintendo or the broader security research community.
The poster's step-by-step requirements and the temporary nature of access are factual descriptions of the claim as made public.
Historically, Nintendo has released software updates to patch verified vulnerabilities, and the industry typically monitors such reports closely.
We will continue to follow this story for confirmation from independent researchers or official statements from Nintendo.
For related coverage on Switch hardware, eShop releases and Nintendo news, check our Nintendo Switch hub.
