{"id":"EEF-CVE-2026-75758","summary":"Unbounded recursion between Inspect.List charlist rendering and List.to_string/1 error path in Elixir","details":"## Summary\n\nUncontrolled Recursion vulnerability in the Elixir standard library allows an attacker who controls a list passed to `inspect/1`, `List.to_string/1`, or `List.to_charlist/1` to exhaust a BEAM node's memory.\n\n`Inspect.List`'s charlist branch in `lib/elixir/lib/inspect.ex` classifies a list as a charlist using `List.ascii_printable?/2`, which examines only the first `:printable_limit` (4096 by default) elements, and then calls `IO.chardata_to_string/1` on the whole term. A list whose printable prefix exceeds that limit but which contains a later element that is not a code point (an atom, an out-of-range integer, or an improper tail) is therefore mis-classified, and the conversion raises `ArgumentError`. That conversion runs inside `List.to_string/1`, whose rescue clause builds its message by interpolating `inspect(list)`, which re-enters the same branch and raises again. The nested inspection is an argument to `raise`, so the recursion is not in tail position and every level is retained: the process stack grows monotonically while each cycle re-walks the list, until the process is killed by `max_heap_size` or, by default, the node runs out of memory. `List.to_charlist/1` has the same rescue shape.\n\nBelow the printable limit the inner `inspect/1` sees the invalid element within its counter and renders the list in ordinary bracket form, so a single `ArgumentError` is raised and no recursion occurs.\n\nThis issue affects elixir: from 1.15.0-rc.0 before 1.18.5, from 1.19.0-rc.0 before 1.19.6, and from 1.20.0-rc.0 before 1.20.4.\n\n## Workarounds\n\nInstall a global inspect function that renders lists as lists rather than inferring charlists, by calling `Inspect.Opts.default_inspect_fun/1` with `fn term, opts -\u003e Inspect.inspect(term, %{opts | charlists: :as_lists}) end` from the application's start callback. This keeps the charlist branch from being entered at all, so the mis-inferred conversion never raises and the error path cannot recurse.\n\nThe trade-off is global: charlists then render in bracket form, so `~c\"abc\"` inspects as `[97, 98, 99]` everywhere in the application, including in logs and error reports.","aliases":["CVE-2026-75758","GHSA-jf5q-v438-665c"],"modified":"2026-09-08T03:45:03.806286773Z","published":"2026-08-28T11:28:53.505Z","database_specific":{"capec_ids":["CAPEC-130"],"cpe_ids":["cpe:2.3:a:elixir-lang:elixir:*:*:*:*:*:*:*:*"],"cwe_ids":["CWE-674"]},"references":[{"type":"ADVISORY","url":"https://github.com/elixir-lang/elixir/security/advisories/GHSA-jf5q-v438-665c"},{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-75758.html"},{"type":"FIX","url":"https://github.com/elixir-lang/elixir/commit/1eff1acffd49bdcc0d7f57ca74c1603328eed68a"},{"type":"FIX","url":"https://github.com/elixir-lang/elixir/commit/5230d73968f1b4969d2a2646786fa6c71475f5cc"},{"type":"FIX","url":"https://github.com/elixir-lang/elixir/commit/a983c8c043b1fbf1d95df78a29149222dac2988c"},{"type":"FIX","url":"https://github.com/elixir-lang/elixir/commit/0bba5887577b1e328da825bd018815fdc519685a"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/elixir-lang/elixir","events":[{"introduced":"9718f2b90ce086ff8614d5782f4ec528495c98dd"},{"fixed":"1eff1acffd49bdcc0d7f57ca74c1603328eed68a"},{"fixed":"5230d73968f1b4969d2a2646786fa6c71475f5cc"},{"fixed":"a983c8c043b1fbf1d95df78a29149222dac2988c"},{"fixed":"0bba5887577b1e328da825bd018815fdc519685a"}]}],"versions":["v1.18-latest","v1.19.5","v1.19-latest","v1.20.3","v1.20-latest","main-latest","v1.20.2","v1.20.1","v1.20.0","v1.20.0-rc.6","v1.20.0-rc.5","v1.20.0-rc.4","v1.20.0-rc.3","v1.20.0-rc.2","v1.20.0-rc.1","v1.20.0-rc.0","v1.19.4","v1.19.3","v1.19.2","v1.19.1","v1.19.0","v1.19.0-rc.2","v1.19.0-rc.1","v1.19.0-rc.0","v1.18.4","v1.18.3","v1.18.2","v1.18.1","v1.18.0","v1.18.0-rc.0","v1.15.0-rc.1","v1.15.0-rc.0"],"database_specific":{"source":"https://cna.erlef.org/osv/EEF-CVE-2026-75758.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"}],"credits":[{"name":"Thomas Cioppettini / Scalpel Software Inc","type":"REPORTER"},{"name":"José Valim","type":"REMEDIATION_DEVELOPER"},{"name":"Jonatan Männchen / EEF","type":"COORDINATOR"}]}