CVE-2026-71867: Orval RCE via property name injection in MSW mock generator

CVE-2026-71867 · Severity: critical · CVSS 4 · Published 2026-08-19

Orval is a popular code generation tool that creates mock API responses for testing. When generating MSW (Mock Service Worker) mocks, the tool fails to properly escape schema property names, allowing an attacker to inject arbitrary JavaScript code into the generated mock factory functions. An attacker who controls the API specification can craft malicious property names that execute arbitrary code (including system commands) on any developer's machine that generates and runs the mocks in tests.

Technologies: orval (npm). Vendors: npm.

Quick answers

Is CVE-2026-71867 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-71867 being exploited in the wild.
How severe is CVE-2026-71867?
Critical severity, with a CVSS score of 4, published 19 August 2026.
Which products and versions are affected?
orval (npm) < 8.21.0, SEMVER:introduced=0,fixed=8.21.0.
Is there a fix for CVE-2026-71867?
Yes. orval (npm): upgrade to 8.21.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-71867 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-71867?
Check whether you run orval (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • orval (npm): upgrade to 8.21.0 or later
    npm install orval@8.21.0

Technical details

The vulnerability is an injection flaw (CWE-95, eval injection) in Orval's MSW mock generator. When processing OpenAPI/schema property names, Orval emits them directly into generated JavaScript code using single quotes without escaping: `{'propertyName': value}`. A property name containing a single quote closes the string literal and lands in object-literal context, where a computed property key `[expr]` is evaluated at mock factory call time (e.g., during test execution). An attacker-controlled API specification can include a property like `x': 0, [require("fs").writeFileSync("marker","")]: 0, 'y` to achieve code execution. The fix is to escape property names using JSON.stringify or equivalent. The vulnerability is confirmed in versions prior to 8.21.0 and has been patched in 8.21.0 and later.

Affected products

  • orval-labs orval < 8.21.0

Identifiers

  • CVE-2026-71867
  • GHSA-2w86-xfrc-g85r

Timeline

  • 2026-09-03: disclosed
  • 2026-09-03: patched: Version 8.21.0 released with fix

References

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