CVE-2026-62681: Orval: RCE via OpenAPI path -> unescaped request-URL template literal (backtick breakout)
Summary
Orval emits the OpenAPI path into the generated request URL as a TEMPLATE LITERAL ( /users/... ) without escaping the backtick character. A path containing a backtick closes the template literal and injects a concatenation expression that is evaluated when the generated URL/request/key function is called, executing attacker-controlled code. Affects the axios, fetch, react-query, and swr clients. Verified on Orval 8.19.0; survives Orval's default OpenAPI validation.
Details
ts // generated URL builder (fetch client) return /users/ + (globalThis.X = require("fs").writeFileSync("/marker","pwned")) + /list;
The backtick in the path terminates the ... literal; + (<code>) + runs as a live expression; a trailing backtick reopens a template literal so the file stays valid. The code runs whenever the generated request function, URL builder, or query-key function is called.
This is distinct from Orval's four published CVEs: CVE-2026-22785 (summary -> MCP server), CVE-2026-23947 / CVE-2026-25141 (x-enumDescriptions), and CVE-2026-24132 (const -> mock files). This is a different field (the route path) and a different sink (the request-URL template literal), which those advisories and their fixes do not cover.
PoC
reproduce.sh (+ makespec.py) attached: generates a fetch client with default validation, bundles it, calls the generated functions, and shows a marker file written. Verified on 8.19.0.
Impact
Code execution in any environment that calls a client generated from an attacker-controlled or attacker-influenced OpenAPI description (developer, CI, or the running application).
Suggested fix
Escape the path before emitting it into the URL template literal (escape backtick and ${, or build the URL with an encoder that treats the path as data), and validate path characters.
Other sources
Orval generates type-safe JavaScript clients in TypeScript from OpenAPI v3 and Swagger v2 specifications. Prior to 8.21.0, an unescaped backtick in an OpenAPI path is emitted into request URL template literals generated for axios, fetch, react-query, and SWR clients without safe encoding. This permits attacker-controlled JavaScript to be evaluated when a generated request, URL-builder, or query-key function is called, resulting in code execution in the developer, CI, test, or application environment. The affected code is packages/core/src/getters/route.ts and route generation consumers. This issue is fixed in version 8.21.0.
— MITRE
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
npm/orvalto a version that resolves this vulnerability.Fixed in 8.21.0 - Upgrade
Upgrade
Orvalto a version that resolves this vulnerability.Fixed in 8.21.0 - Configuration
When generating axios/fetch/react-query/SWR request URL template literals from OpenAPI route paths, escape backtick and `${` (or use a URL builder/encoder that treats the path as data) and validate allowed path characters so the OpenAPI path cannot break out of the `` `...` `` template literal.
Orval (generated client code generation for request URL template literals) Escape OpenAPI path before emitting into TEMPLATE LITERAL = escape backtick (`` ` ``) and `${` sequences, or build URL using an encoder that treats the path as data; validate path characters
Event History
Frequently Asked Questions
Who is exposed to this issue?
Teams using Orval before 8.21.0 to generate axios, fetch, react-query, or SWR clients from OpenAPI v3 or Swagger v2 specifications are exposed when a processed specification contains an attacker-controlled backtick in a path.
What must happen for code execution to occur?
An attacker must cause a malicious OpenAPI path to be included in generated code, and a generated request, URL-builder, or query-key function containing that path must be called. The injected JavaScript then executes in the developer, CI, test, or application environment where that generated code runs.
Which versions contain the fix?
The issue is fixed in Orval 8.21.0. Versions prior to 8.21.0 are affected.
How can I determine whether generated code is affected?
Review the OpenAPI or Swagger specifications used for generation for path values containing backticks, then inspect generated request URL template literals and related URL-builder or query-key functions. A backtick emitted unescaped into those generated template literals indicates exposure.