CVE-2026-82732

Declared argument constraints not enforced on AshTypescript typed controller routes

Published Sep 1, 2026 CVSS 4.0 · 6.3 Medium EPSS < 1% KEV · Not listed
Description
Improper Input Validation vulnerability in ash-project ash_typescript allows a remote attacker to submit argument values outside a declared allowlist or bound on typed-controller routes.

AshTypescript.TypedController.RequestHandler in lib/ash_typescript/typed_controller/request_handler.ex calls Ash.Type.cast_input/3 and treats an {:ok, cast} result as fully validated. In Ash these are separate steps: cast_input/3 only coerces the term, while every constraint declared on the argument is applied by Ash.Type.apply_constraints/3, which this path never calls. Constraints such as one_of, max_length, min and max, and match are therefore inert, so a value outside a declared allowlist is accepted and passed to the route handler. Codegen renders the same constraints into the generated TypeScript types, so an allowlist appears enforced to a TypeScript caller while any other HTTP client ignores it. Empty-string to nil normalization also lives in apply_constraints, so the allow_nil?: false check accepts "" for a required argument.

Where a constraint gates a role, a status, or a sort direction, this becomes a privilege or state-machine bypass.

This issue affects ash_typescript: from 0.15.0 before 0.18.0.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Improper Input Validation vulnerability in ash-project ash_typescript allows a remote attacker to submit argument values outside a declared allowlist or bound on typed-controller routes. AshTypescript.TypedController.RequestHandler in lib/ash_typescript/typed_controller/request_handler.ex calls Ash.Type.cast_input/3 and treats an {:ok, cast} result as fully validated. In Ash these are separate steps: cast_input/3 only coerces the term, while every constraint declared on the argument is applied by Ash.Type.apply_constraints/3, which this path never calls. Constraints such as one_of, max_length, min and max, and match are therefore inert, so a value outside a declared allowlist is accepted and passed to the route handler. Codegen renders the same constraints into the generated TypeScript types, so an allowlist appears enforced to a TypeScript caller while any other HTTP client ignores it. Empty-string to nil normalization also lives in apply_constraints, so the allow_nil?: false check accepts "" for a required argument. Where a constraint gates a role, a status, or a sort direction, this becomes a privilege or state-machine bypass. This issue affects ash_typescript: from 0.15.0 before 0.18.0.
Title Declared argument constraints not enforced on AshTypescript typed controller routes
First Time appeared Ash-project
Ash-project ash Typescript
Weaknesses CWE-20
CPEs cpe:2.3:a:ash-project:ash_typescript:*:*:*:*:*:*:*:*
Vendors & Products Ash-project
Ash-project ash Typescript
References
Metrics cvssV4_0

{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
EEF
Published
Updated
Sep 1, 2026, 2:55 PM
Reserved
Aug 31, 2026, 12:59 AM
Status
Deferred
Published
Sep 1, 2026, 3:16 AM
Modified
Sep 1, 2026, 9:15 PM