The vulnerability exists in ash-typescript’s result processor. When a field policy denies an attribute, Ash substitutes a %Ash.ForbiddenField{} marker that preserves the real value in the original_value field. The normalize_primitive/1 code path does not strip this marker, so the value is serialized and returned to the caller, allowing an unauthorized RPC user to read data that should have been protected. This flaw results in unauthorized disclosure of sensitive attribute values.

ash-project ash_typescript is affected in all releases from 0.11.0 up to but not including 0.18.0. Any deployment of these versions that exposes the RPC interface for returning embedded resources is vulnerable.

The CVSS score of 8.2 highlights a high-severity information‑disclosure issue. EPSS data is not available, so the exact probability of exploitation cannot be quantified, but the vulnerability is actionable through the public RPC endpoint. An attacker who can invoke RPC calls that return embedded resources, such as normalizing a value or processing a returned struct, can trigger the flaw and obtain forbidden field values. The attack is feasible over the network if the RPC service is exposed, making the risk significant for systems with less restrictive access controls. The vulnerability is not listed in CISA KEV, but the high CVSS score warrants timely remediation.