CVE-2026-72716: Orval: Import-time RCE via query-parameter default -> zod module-level template literal
Summary
Orval's zod schema generation emits the query-parameter default value as a module-level template literal (export const …Default = <default>;) without escaping ${ or the backtick. A default of the form v${<code>}w injects a live JavaScript expression evaluated when the generated zod schema module is imported, executing attacker-controlled code at import — no request or function call needed. Verified on Orval 8.19.0; survives default OpenAPI validation.
Details
ts export const …Default = v${globalThis.ORVPWN()}w; // ${...} = arbitrary JS expression, runs at import
Malicious input: a query parameter with a default of v${<attacker JS>}w. ${...} permits any JS expression.
Note: this is one of several default-bearing positions that reach the same unescaped zod template-literal sink; a single fix (escape default values) closes all of them, and a CNA may choose to consolidate the related reports.
PoC
reproduce.sh (+ makespec.py) attached: generates the zod schema with default validation, bundles it, imports it, and shows a marker written at import. Verified on 8.19.0.
Impact
Code execution at import in any application that imports a zod schema module generated from an attacker-controlled or attacker-influenced OpenAPI description.
Suggested fix
Emit default values via a proper string-literal encoder (JSON.stringify, or escape backtick and ${ if a template literal must be used); never interpolate a spec value into a template literal. Apply to every default position. maintainer-report.txt makespec.py reproduce.sh
Other sources
Orval generates type-safe JavaScript clients in TypeScript from OpenAPI v3 and Swagger v2 specifications. Prior to 8.21.0, a ${...} expression or backtick in a query parameter default is emitted into a module-level template literal emitted by zod schema generation without safe encoding. This permits attacker-controlled JavaScript to be evaluated when the generated zod schema module is imported, resulting in code execution in the developer, CI, test, or application environment. The affected code is packages/zod/src/index.ts function formatDefaultValue. This issue is fixed in version 8.21.0.
— MITRE
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
npm/orvalto a version that resolves this vulnerability.Fixed in 8.21.0 - Upgrade
Upgrade
orvalto a version that resolves this vulnerability.Fixed in 8.21.0 - Configuration
In formatDefaultValue, emit query-parameter `default` values using a proper string-literal encoder (e.g., JSON.stringify) or, if a template literal must be used, escape backticks and the `${` sequence so `${...}` expressions cannot be injected into the generated zod schema module template literal.
Orval zod schema generation (packages/zod/src/index.ts function formatDefaultValue) module-level template literal encoding for query-parameter default values = Escape backticks and `${` (use a proper string-literal encoder such as JSON.stringify)
Event History
Frequently Asked Questions
Who is exposed to code execution from this issue?
Users of Orval before 8.21.0 are exposed when they generate Zod schemas from an OpenAPI or Swagger specification containing a malicious query-parameter default and then import the generated schema module. Code runs in the environment performing that import, such as a developer workstation, CI job, test environment, or application runtime.
What must an attacker control to exploit it?
The attacker needs to supply or influence an API specification with a query parameter default containing a ${...} expression or a backtick. Exploitation also requires that the affected Zod schema generation path is used and that the resulting generated module is imported.
How can I determine whether generated output may already be affected?
Review OpenAPI or Swagger inputs used with affected Orval versions for query parameter default values containing backticks or ${...} expressions. Also inspect generated Zod schema modules, since the unsafe value is emitted into a module-level template literal and executes on import.
What is the available fix?
Upgrade Orval to version 8.21.0, which fixes the unsafe handling in the Zod generator's formatDefaultValue function. Until upgraded, avoid generating or importing Zod schema output from untrusted or unreviewed API specifications.