Developer Zhouwei Zhang revealed on Twitter that he was able to change the font of the iOS system without a jailbreak.
To do this, it used the CVE-2022-46689 exploit found in iOS 16.1.2 and earlier versions of the operating system. Allows applications to execute arbitrary code with kernel privileges.
Zhang noted that the change only affects some text on iOS, as other parts of the system use different fonts.
To try out the font changing application yourself, you will need to download the entire source code from Git Hub and compile the program yourself via Xcode or manually sign the IPA file with a developer certificate.