CVE-2026-42047 — inngest
HIGHCVE-2026-42047 is a high-severity (CVSS 8.6) Information Exposure vulnerability in inngest. A fix is available for inngest — see the affected versions and patch details below.
Inngest TypeScript SDK exposes environment variables via serve() handler on unhandled HTTP methods
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.
- 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-2026-42047.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
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.
inngestnpmDescription
Summary
A vulnerability in the Inngest TypeScript SDK versions 3.22.0 through 3.53.1 allows unauthenticated remote attackers to exfiltrate environment variables from the host process via the serve() HTTP handler.
The serve() handler implements GET, POST, and PUT methods. Requests using PATCH, OPTIONS, or DELETE fall through to a generic handler that returns diagnostic information. A change introduced in v3.22.0 caused this diagnostic response to include the contents of process.env, exposing any secrets, API keys, or credentials present in the environment.
Who is affected
An application is vulnerable if all of the following are true:
- It uses
inngestSDK version>= 3.22.0, <= 3.53.1(inclusive) - Its
serve()endpoint is reachable viaPATCH,OPTIONS, orDELETErequests.
Please check your framework's implementation for the serve handler (documentation) to asses whether it handles these HTTP methods. Common vulnerable configurations include:
- Next.js Pages Router, which forwards all HTTP methods to the handler.
- Express via
app.use('/api/inngest', serve(...)), which routesPATCHandOPTIONSto the handler by default.
The following are not affected:
- Next.js App Router handlers that explicitly export only
GET,POST, andPUT. - Applications using the
connectworker method. - SDK versions
< 3.22.0and>= 3.54.0, including all4.xreleases.
The vulnerability was responsibly disclosed by an Inngest user. At this time, there are no known reports of exploitation.
Remediation
- Upgrade to
[email protected]or later. The fix is backwards compatible with the3.xrelease line. The4.xline is also unaffected. - Rotate any secrets that were presence in environment variables (
process.env) within affected environments including Inngest signing keys and event keys - Search logs for any requests to your
serveendpoints using thePATCH,OPTIONS,DELETEhttp methods to assess if any environment variables may have been exposed.
Additional recommendations
Users on platforms with long-lived deployments (e.g. Vercel, Cloudflare Workers) should be aware that prior deployments remain reachable at their immutable URLs and may continue to expose the vulnerability even after a new deployment is promoted. For example, Vercel offers security features such as "Deployment Protection" and the ability to delete older deployments which can help immediately mitigate impact.
For additional security, users can also adjust firewall or proxy rules to only allow requests to their serve endpoint from Inngest IP addresses available here: http://inngest.com/ips-v4, http://inngest.com/ips-v6
Workarounds
If upgrading is not immediately possible, restrict the serve() endpoint at the framework or reverse-proxy layer to accept only GET, POST, and PUT. The Inngest serve() endpoint does not require any other HTTP methods.
Resources
- Rotating Inngest keys: https://www.inngest.com/docs/platform/manage/rotating-keys
- Inngest signing keys: https://www.inngest.com/docs/platform/signing-keys
- Inngest event keys: https://www.inngest.com/docs/events/creating-an-event-key
- Inngest security best practices: https://www.inngest.com/docs/learn/security
Credits
- Ben Hylak - an independent security researcher, discovered and responsibly disclosed the vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | inngest | ≥ 3.22.0&&< 3.54.0 | 3.54.0npm install inngest@3.54.0 |
Affected Products
inngestinngestDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for inngest, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update inngest to 3.54.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-42047 is resolved across your whole dependency graph.
Workarounds
Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.
Frequently Asked Questions
Is CVE-2026-42047 in your dependencies?
Find it across npm, including transitive dependencies.