CVE-2026-82730Authorization-redacted field values disclosed through AshTypescript result normalization

Official description

Incorrect Authorization vulnerability in ash-project ash_typescript allows an unauthorized RPC caller to read attribute values that Ash field policies denied. When a field policy denies an attribute, Ash substitutes %Ash.ForbiddenField{}, which retains the real value in original_value because embedded resources must remain writable, and hides it from Inspect rather than removing it. AshTypescript.Rpc.ResultProcessor strips these markers to nil on its template-driven paths, but normalize_primitive/1 in lib/ash_typescript/rpc/result_processor.ex had no such clause, so a marker fell through to the generic struct branch which calls Map.from_struct/1 and serializes every key, original_value included. The denied value is returned to the caller inside the marker that represents its own denial. The simplest trigger is an action returning an embedded resource as a map, which routes through normalize_resource_struct/2 with an empty template. normalize_value_for_json/1 is a public, unguarded entry point to the same path. This issue affects ash_typescript: from 0.11.0 before 0.18.0.

Affected products (as reported)

References

• https://github.com/ash-project/ash_typescript/security/advisories/GHSA-6929-rjmh-4x62 related, vendor-advisory
• https://cna.erlef.org/cves/CVE-2026-82730.html related
• https://osv.dev/vulnerability/EEF-CVE-2026-82730 related
• https://github.com/ash-project/ash_typescript/commit/aa7f9f1967b0bec806ac1156142267e805d70a55 patch