Since 17.4, webassembly does not work in app webviews or Safari when in lockdown mode, even when an exception is added. Previously, if you were in lockdown mode, and added an exception, the app or website would work normally. A simple way to test this is to visit a wasm feature detector like: https://wasm-feature-detect.surma.technology/ Expected behavior (how it worked in 17.3): no features detected when in lockdown mode. Add a lockdown exception for this site. Now wasm features are detected. Impacted apps I'm aware of: Standard Notes https://github.com/standardnotes/forum/issues/3514 Bitwarden https://www.reddit.com/r/Bitwarden/comments/1bbaj8w/cannot_log_in_to_new_web_interface_on_ios_with/ Mutiny Wallet https://github.com/MutinyWallet/mutiny-web/issues/993 All of these rely on some webassembly behavior.
<rdar://problem/127701515>