"unc0ver v7.0.1 is NOW OUT with major stability and reliability improvements for all versions including Fugu14 devices and built-in Fugu14 support with AltStore 1.4.8. https://unc0ver.dev"
Once AltStore 1.4.8 has been installed, the app will guide you through the installation of Fugu14 and unc0ver 7.0.1 on devices running iOS 14.4 to iOS 14.5.1.
Fugu14 is an (incomplete) iOS 14 Jailbreak, including an untether (persistence), kernel exploit, kernel PAC bypass and PPL bypass. The CVE numbers of the vulnerabilities are: CVE-2021-30740, CVE-2021-30768, CVE-2021-30769, CVE-2021-30770 and CVE-2021-30773.
According to its GitHub page, Fugu14 should eventually support all arm64e devices (iPhone XS and newer) on iOS 14.3 - 14.5.1. Support for lower versions (down to 14.2) can be added by editing arm/shared/ClosurePwn/Sources/ClosurePwn/PwnClosure.swift and arm/shared/KernelExploit/Sources/KernelExploit/offsets.swift.