9.3

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4.0

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CVE-2026-23947

CVE-2026-23947: Orval has a code injection via unsanitized x-enum-descriptions in enum generation

Impact

Arbitrary code execution in environments consuming generated clients

This issue is similar in nature to the recently-patched MCP vulnerability (CVE-2026-22785), but affects a different code path in @orval/core that was not addressed by that fix.

The vulnerability allows untrusted OpenAPI specifications to inject arbitrary TypeScript/JavaScript code into generated clients via the x-enumDescriptions field, which is embedded without proper escaping in getEnumImplementation(). I have confirmed that the injection occurs during const enum generation and results in executable code within the generated schema files.

Patches

Upgrade to Orval 8.0.2

References

An example OpenAPI showing the issue:

openapi: 3.0.4
info:
  title: Enum PoC
  version: "1.0.0"

paths:
  /ping:
    get:
      operationId: ping
      responses:
        "200":
          description: ok
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/EvilEnum"

components:
  schemas:
    EvilEnum:
      type: string
      enum:
        - PWNED
      x-enumDescriptions:
        - "pwned */ require('child_process').execSync('id'); /*"

(GitHub Advisory)

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CVE-2026-23947

CVE-2026-23947:

9.3

CVSS Score

4.0

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Technical Details

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
@orval/core	npm	>= 8.0.0-rc.0, < 8.0.2	8.0.2
@orval/core	npm	< 7.19.0	7.19.0

Technical Details

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Root Cause Analysis

The vulnerability lies in the @orval/core package, where unsanitized data from an OpenAPI specification is used to generate client-side code. The analysis of the provided patch commit 9e5d93533904936678ba93b5d20f6bca176a4e1e reveals that the functions getEnumDescriptions and getEnumNames in packages/core/src/getters/enum.ts were responsible for reading potentially malicious values from the OpenAPI schema.

The vulnerability description explicitly mentions that the x-enumDescriptions field is embedded without proper escaping in getEnumImplementation(). The patch confirms this by showing that getEnumDescriptions (and also getEnumNames) originally returned the raw values. An attacker could provide a malicious string containing JavaScript code in the x-enumDescriptions or x-enumNames fields of an OpenAPI document. When Orval processes this document, these functions would read the malicious string, which would then be embedded into the generated TypeScript/JavaScript code, leading to arbitrary code execution in the environment that consumes the generated client.

The fix involves calling a newly imported jsStringEscape function on each description and name, which neutralizes any special characters and prevents them from being interpreted as code. Therefore, during exploitation, the getEnumDescriptions and getEnumNames functions would be the ones processing the malicious input just before it gets injected.

Vulnerable functions

getEnumDescriptions

packages/core/src/getters/enum.ts

The function `getEnumDescriptions` retrieves enum descriptions from an OpenAPI schema. Before the patch, it directly returned the values from `x-enumDescriptions` without any sanitization. This allowed an attacker to inject arbitrary code into the generated client by crafting a malicious OpenAPI specification, as the description was embedded directly into a template.

getEnumNames

packages/core/src/getters/enum.ts

The function `getEnumNames` retrieves enum names from an OpenAPI schema. Similar to `getEnumDescriptions`, this function was vulnerable because it did not sanitize the input from fields like `x-enumNames`. The patch adds escaping via `jsStringEscape` to prevent code injection.

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WAF Protection Rules

WAF Rule

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Reasoning

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CVE-2026-23947: Orval has a code injection via unsanitized x-enum-descriptions in enum generation

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References

CVE-2026-23947:

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Reasoning

CVE-2026-23947: Orval has a code injection via unsanitized x-enum-descriptions in enum generation

Impact

Patches

References

9.3

9.3

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