CVE-2026-42047
HIGHCVE-2026-42047 is a high-severity (CVSS 8.6) Information Exposure vulnerability in inngest. O3 Security confirms whether CVE-2026-42047 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
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
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-42047 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 356,453 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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
Inngest is a platform for running event-driven and scheduled background functions with queueing, retries, and step orchestration. Versions 3.22.0 through 3.53.1 contain a vulnerability that 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. An application is vulnerable if its serve() endpoint is reachable via PATCH, OPTIONS, or DELETE requests, which is common in setups like Next.js Pages Router or Express's app.use(...). Not affected are Next.js App Router handlers that export only GET, POST, and PUT, and applications using the connect worker method. This issue has been fixed in version 3.54.0. To work around this issue 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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | inngest | ≥ 3.22.0&&< 3.54.0 | 3.54.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for inngest. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
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
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-42047 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-42047. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-42047 in your dependencies?
O3 detects CVE-2026-42047 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.