# Elixir v1.20.4

- Product: Elixir (https://whatsnew.fyi/product/elixir)
- Vendor: Elixir
- Date: 2026-08-28
- Version: v1.20.4
- Original notes: https://github.com/elixir-lang/elixir/releases/tag/v1.20.4
- Permalink: https://whatsnew.fyi/product/elixir/releases/v1.20.4

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

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- **security** — Avoid recursion when invalid charlists are given to List.to_string/1 or List.to_charlist/1
- **fixed** — Fix false positives in Base64 validation
- **fixed** — Fix inferred type of :erlang.split_binary/2 when given a bitstring
- **fixed** — Fix type checker crash on comprehensions with a non-returning :into expression
- **fixed** — Fix final sigma handling in Greek casing
- **fixed** — Fix Task.yield_many/2 waiting indefinitely when :limit exceeds the task count

###### 1. Security

  * [List] Avoid recursion when invalid charlists are given to `List.to_string/1` or `List.to_charlist/1` (CVE-2026-75758, GHSA-jf5q-v438-665c)

###### 2. Bug fixes

###### Elixir

  * [Base] Fix false positives in Base64 validation
  * [Kernel] Fix inferred type of `:erlang.split_binary/2` when given a bitstring
  * [Kernel] Fix type checker crash on comprehensions with a non-returning `:into` expression
  * [String] Fix final sigma handling in Greek casing
  * [Task] Fix `Task.yield_many/2` waiting indefinitely when `:limit` exceeds the task count