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

High 8.2 Published Updated

An attacker can read sensitive attribute values denied by field policies due to improper serialization of forbidden field markers in AshTypescript RPC results.

Exploited in the wild
Not known
Login needed
Not needed
Attackable
Over the internet
Victim action needed
Not needed
Fix
Available

What is CVE-2026-82730?

CVE-2026-82730 is a high-severity vulnerability in ash-project ash_typescript, published on 1 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

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.

Weakness: CWE-863

Which versions are affected by CVE-2026-82730?

1 open source package ship an affected version, including ash_typescript.

PackageAffectedFixed in
ash_typescript HexFrom 0.11.00.18.0

How do I fix CVE-2026-82730?

Upgrade ash_typescript to 0.18.0 or later.

Is CVE-2026-82730 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-82730 exists.

Sources

Also known as EEF-CVE-2026-82730, GHSA-6929-rjmh-4x62.

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