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CVE-2026-23947

Orval MCP client is vulnerable to code injection via unsanitized x-enum-descriptions in enum generation

9.3 CriticalPublic exploitFix available

CVE-2026-23947 is a critical vulnerability (CVSS 9.3) in Orval, published January 20, 2026. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 0.84%, the 57th percentile. Fixed in @orval/core 8.0.2.

Orval generates type-safe JS clients (TypeScript) from any valid OpenAPI v3 or Swagger v2 specification. Versions prior to 7.19.0 until 8.0.2 are vulnerable to arbitrary code execution in environments consuming generated clients. This issue is similar in nature to CVE-2026-22785, but affects a different code path in @orval/core that was not addressed by CVE-2026-22785's 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. Orval 7.19.0 and 8.0.2 contain a fix for the issue.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
High

Exploit likelihood

0.84%Up 0.8 points since Jan 20, 2026
90%50%10%1%

What each source reports

CVE List Score used 9.3

Orval MCP client is vulnerable to code injection via unsanitized x-enum-descriptions in enum generation

Orval generates type-safe JS clients (TypeScript) from any valid OpenAPI v3 or Swagger v2 specification. Versions prior to 7.19.0 until 8.0.2 are vulnerable to arbitrary code execution in environments consuming generated clients. This issue is similar in nature to CVE-2026-22785, but affects a different code path in @orval/core that was not addressed by CVE-2026-22785's 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. Orval 7.19.0 and 8.0.2 contain a fix for the issue.

Record
CVE-2026-23947
CVSS 4.0
9.3 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Weakness
CWE-77
Updated
2026-11-02
EUVDEUVD-2026-3590 9.3

Orval generates type-safe JS clients (TypeScript) from any valid OpenAPI v3 or Swagger v2 specification. Versions prior to 7.19.0 until 8.0.2 are vulnerable to arbitrary code execution in environments consuming generated clients. This issue is similar in nature to CVE-2026-22785, but affects a different code path in @orval/core that was not addressed by CVE-2026-22785's 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. Orval 7.19.0 and 8.0.2 contain a fix for the issue.

Record
EUVD-2026-3590
CVSS 4.0
9.3 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-h526-wf6g-67jv 9.3

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'); /*"
Record
GHSA-h526-wf6g-67jv
CVSS 4.0
9.3 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Weakness
CWE-77, CWE-94
Updated
2026-11-02
NVD 9.3

Orval generates type-safe JS clients (TypeScript) from any valid OpenAPI v3 or Swagger v2 specification. Versions prior to 7.19.0 until 8.0.2 are vulnerable to arbitrary code execution in environments consuming generated clients. This issue is similar in nature to CVE-2026-22785, but affects a different code path in @orval/core that was not addressed by CVE-2026-22785's 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. Orval 7.19.0 and 8.0.2 contain a fix for the issue.

Record
CVE-2026-23947
CVSS 4.0
9.3 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-77, CWE-94
Updated
2026-11-02
OSV 9.3

Orval MCP client is vulnerable to code injection via unsanitized x-enum-descriptions in enum generation

Orval generates type-safe JS clients (TypeScript) from any valid OpenAPI v3 or Swagger v2 specification. Versions prior to 7.19.0 until 8.0.2 are vulnerable to arbitrary code execution in environments consuming generated clients. This issue is similar in nature to CVE-2026-22785, but affects a different code path in @orval/core that was not addressed by CVE-2026-22785's 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. Orval 7.19.0 and 8.0.2 contain a fix for the issue.

Record
CVE-2026-23947
CVSS 4.0
9.3 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Weakness
CWE-77
Updated
2026-11-02
OSVGHSA-h526-wf6g-67jv 9.3

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'); /*"
Record
GHSA-h526-wf6g-67jv
CVSS 4.0
9.3 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Weakness
CWE-77, CWE-94
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
@orval/core
npm
 8.0.0-rc.0 up to 8.0.2
8.0.2
@orval/core
npm
 before 7.19.0
7.19.0

Public exploits

Links only. Every CVE stores no exploit code.

Public exploits
SourceLinkDate
PoC in GitHubboroeurnprach/CVE-2026-23947-PoC2026-01-21

History

History
WhenChangedSources
2026-11-02createdCVE List, EUVD, GitHub Advisories, NVD, OSV, PoC in GitHub

References

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