published October 12, 2026
Generation of Error Message Containing Sensitive Information vulnerability in ash-project ash_typescript allows an unauthenticated attacker to read internal Elixir terms from an RPC error response by provoking an error the error builder has no dedicated clause for.
AshTypescript.Rpc.ErrorBuilder.build_error_response/1 in lib/ash_typescript/rpc/error_builder.ex renders a pipeline error term that matches no specific clause with inspect/1 and places the result in details.error of the client-facing error. Ash exceptions take a separate path in AshTypescript.Rpc.Errors where unhandled cases are redacted behind an errorId, but these fallbacks have no redaction, so whatever the term carries reaches the HTTP or channel response. Two request paths hand it such terms: a struct-typed action argument with an invalid nested value, where cast_map_to_struct/2 in lib/ash_typescript/rpc/input_formatter.ex throws the raw Ash.Type cast error into the builder, and field selection on a generic action that returns a primitive, where format_field_type/1 inspects the full Ash.Info.Manifest.Type struct into vars.returnType. Resource module names in vars.resource are not treated as sensitive and are out of scope.
This issue affects ash_typescript: from 0.1.0 before 0.19.1.