How severe is CVE-2026-23947?

No CVSS score has been assigned to CVE-2026-23947 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-23947?

CVE-2026-23947 affects the following packages: @orval/core (npm), @orval/core (npm). Ecosystems affected: npm.

How do I fix CVE-2026-23947?

Update @orval/core to 8.0.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-23947 is resolved across your whole dependency graph.

How do I detect CVE-2026-23947 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @orval/core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-23947 if there is no patch (or I can't update yet)?

Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Is CVE-2026-23947 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-23947 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-23947?

CVE-2026-23947 has an EPSS (Exploit Prediction Scoring System) score of 0.8%, placing it in the 58th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-23947?

CVE-2026-23947 is classified as CWE-77 (CWE-77), Code Injection (CWE-94). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-23947 published, and has it been updated?

CVE-2026-23947 was published on January 20, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

Not in CISA KEV

CVE-2026-23947 — @orval/core

Fix: orval-labs/orval@9e5d935

CVE-2026-23947 is a CWE-77 vulnerability in @orval/core. A fix is available for @orval/core — see the affected versions and patch details below.

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

Also known asGHSA-h526-wf6g-67jv

Published

Jan 20, 2026

Updated

Oct 28, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
A successful exploit gives an attacker total control of the affected component, not partial access.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-23947.

EPSS Exploitation Probability

via FIRST.org ↗

0.8%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs58th percentile — riskier than 58% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

2 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

26other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

@orval/corenpm

3.8Mdownloads / week

Description

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'); /*"

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@orval/core`	≥ 8.0.0-rc.0&&< 8.0.2	8.0.2`npm install @orval/core@8.0.2`
📦npm	`@orval/core`	all versions	7.19.0`npm install @orval/core@7.19.0`

Affected Products

1 product · 2 configurations

Application

orvalorval

≥ 8.0.0 && < 8.0.2

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @orval/core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @orval/core to 8.0.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-23947 is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.

Frequently Asked Questions

### 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

O3 Security · Impact-Aware SCA

Is CVE-2026-23947 in your dependencies?

Find it across npm, including transitive dependencies.

Scan my dependencies How O3 SCA works