Orval generates type-safe JavaScript clients in TypeScript from OpenAPI v3 and Swagger v2 specifications. Prior to 8.21.0, an unescaped backtick in servers[0].url is emitted into request URL template literals generated when output.baseUrl.getBaseUrlFromSpecification is enabled without safe encoding. This permits attacker-controlled JavaScript to be evaluated when a generated request or URL-builder 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 function getFullRoute. This issue is fixed in version 8.21.0.
Orval generates type-safe JavaScript clients in TypeScript from OpenAPI v3 and Swagger v2 specifications. Prior to 8.21.0, an unescaped backtick in servers[0].url is emitted into request URL template literals generated when output.baseUrl.getBaseUrlFromSpecification is enabled without safe encoding. This permits attacker-controlled JavaScript to be evaluated when a generated request or URL-builder 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 function getFullRoute. This issue is fixed in version 8.21.0.
Orval generates type-safe JavaScript clients in TypeScript from OpenAPI v3 and Swagger v2 specifications. Prior to 8.21.0, an unescaped backtick in servers[0].url is emitted into request URL template literals generated when output.baseUrl.getBaseUrlFromSpecification is enabled without safe encoding. This permits attacker-controlled JavaScript to be evaluated when a generated request or URL-builder 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 function getFullRoute. This issue is fixed in version 8.21.0.
### Summary
When Orval is configured with `output.baseUrl.getBaseUrlFromSpecification: true`, it bakes the spec's `servers[0].url` into the generated request URL as a template literal without escaping the backtick. A server URL containing a backtick closes the template literal and injects a concatenation expression evaluated when the generated URL/request function is called, executing attacker-controlled code. Verified on Orval 8.19.0 (fetch client); survives default OpenAPI validation.
### Details
```ts
return `http://api.x/` + (globalThis.X = require("fs").writeFileSync("/marker","pwned")) + `/v1/u`;
```
Prerequisite: the documented `getBaseUrlFromSpecification: true` option (takes the base URL from the OpenAPI servers block). This is the same output sink as the route-path case (request-URL template literal) reached via the server `url` field. Distinct from Orval's published CVEs (CVE-2026-22785 summary/MCP, CVE-2026-23947 / CVE-2026-25141 x-enumDescriptions, CVE-2026-24132 const/mock).
### PoC
`reproduce.sh` (+ `make_spec.py`) attached: generates a fetch client with `getBaseUrlFromSpecification: true`, bundles it, calls the functions, and shows a marker written. Verified on 8.19.0.
### Impact
With that option enabled, code execution in any environment that calls a client generated from an attacker-controlled or attacker-influenced OpenAPI description.
### Suggested fix
Escape the server URL before emitting it into the URL template literal (escape backtick and `${`), or build the base URL with an encoder that treats it as data; validate the URL.
[maintainer-report.txt](https://github.com/user-attachments/files/29396562/maintainer-report.txt)
[make_spec.py](https://github.com/user-attachments/files/29396563/make_spec.py)
[reproduce.sh](https://github.com/user-attachments/files/29396564/reproduce.sh)
EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.
Original publisher date fields
datePublished: Aug 19, 2026, 5:40:17 PM
dateUpdated: Aug 19, 2026, 6:19:27 PM
No normalized affected-package data is projected for this source revision. The original publisher record may contain additional product and version evidence; this does not establish that a package is unaffected.
NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.
No normalized affected-package data is projected for this source revision. The original publisher record may contain additional product and version evidence; this does not establish that a package is unaffected.