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PHOENIX TIGHTENS SECURITY DOCS AS ELIXIR 1.20 DEPRECATION WAVE HITS
By RepoJournal · Filed · About Elixir & Phoenix · Composed from the cited sources · methodology
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Phoenix and Phoenix LiveView are hardening their security guidance around client-controlled data in channels and LiveView callbacks, while the ecosystem races to adopt Elixir 1.20's new compiler options before warnings flood your builds.
The Phoenix team shipped critical security documentation updates across both core Phoenix and Phoenix LiveView, explicitly warning developers that Channel join/handle_in payloads [1] and LiveView mount/handle_params/handle_event callbacks [2] receive client-controlled data that must be validated before use. These aren't code changes, they're wake-up calls: if your app trusts these inputs blindly, you have a vulnerability. The docs even include a matching fix to a code example that was missing parentheses [3], so check those tutorials before you ship.
On the tooling front, Phoenix LiveView pre-emptively migrated away from Elixir 1.20's deprecated xref configuration [4], replacing it with the new elixirc_options syntax. If you're running Elixir 1.20, your mix compile command is already screaming warnings about this. LiveView got ahead of it; your projects should too. The Elixir core team also merged documentation improvements for recently added environment variables [6], and LiveView is cleaning up internal doc references [5].
Action items
- → Audit Channel handlers and LiveView callbacks for client data validation before next deploy phoenixframework/phoenix [plan]
- → Migrate xref: [exclude: ...] to elixirc_options: [no_warn_undefined: ...] in mix.exs if on Elixir 1.20+ phoenixframework/phoenix_live_view [plan]
- → Review LiveView security model guide for the parenthesis fix if you've been using the code examples phoenixframework/phoenix_live_view [monitor]
References
- [1] Add security notes for Channel join / handle_in payload (#6707) ↗ phoenixframework/phoenix
- [2] Add security notes for mount, handle_params, and handle_event (#4284) ↗ phoenixframework/phoenix_live_view
- [3] Fix missing parenthesis in Security Model example (#4283) ↗ phoenixframework/phoenix_live_view
- [4] Use elixirc_options: [no_warn_undefined: ...] instead of xref: [exclude: ...] (#4281) ↗ phoenixframework/phoenix_live_view
- [5] Replace internal docs references .html -> .md ↗ phoenixframework/phoenix_live_view
- [6] Add since info to recently added env vars (#15458) ↗ elixir-lang/elixir
