CVE-2026-42047: Inngest Exposes Environment Variables via HTTP Handler
The National Vulnerability Database has detailed CVE-2026-42047, a high-severity vulnerability affecting Inngest versions 3.22.0 through 3.53.1. This flaw allows unauthenticated remote attackers to exfiltrate critical environment variables from the host process. The exposure occurs through Inngest’s serve() HTTP handler when accessed via non-standard methods like PATCH, OPTIONS, or DELETE.
A change introduced in version 3.22.0 inadvertently caused the diagnostic response for these methods to include the contents of process.env. This means sensitive data such as API keys, credentials, and other secrets stored as environment variables are directly exposed. Applications are vulnerable if their serve() endpoint is reachable via these methods, a common configuration in frameworks like Next.js Pages Router or Express applications using app.use(...).
Defenders must recognize the severity here. Attackers can gain a foothold by simply probing for these endpoints, bypassing authentication entirely. The National Vulnerability Database confirms that Next.js App Router handlers exporting only GET, POST, and PUT, and applications using the connect worker method, are not affected. The fix is available in Inngest version 3.54.0. For those unable to upgrade immediately, restricting the serve() endpoint to only accept GET, POST, and PUT requests at the framework or reverse-proxy layer is a critical workaround.
What This Means For You
- If your organization uses Inngest, immediately check your version and upgrade to 3.54.0 or later to patch CVE-2026-42047. If immediate patching isn't possible, restrict your `serve()` endpoint to ONLY allow GET, POST, and PUT methods at the framework or reverse-proxy level. Assume any exposed Inngest instance on versions 3.22.0-3.53.1 has already had its environment variables compromised and initiate credential rotation for any secrets that might have been present.
Related ATT&CK Techniques
🛡️ Detection Rules
3 rules · 6 SIEM formats3 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
CVE-2026-42047: Inngest serve() handler exposed environment variables via non-standard HTTP methods
title: CVE-2026-42047: Inngest serve() handler exposed environment variables via non-standard HTTP methods
id: scw-2026-05-07-ai-1
status: experimental
level: high
description: |
Detects the use of non-standard HTTP methods (PATCH, OPTIONS, DELETE) against the Inngest serve() handler. Versions 3.22.0 through 3.53.1 of Inngest are vulnerable, allowing unauthenticated remote attackers to exfiltrate environment variables when these methods are used, as they fall through to a generic handler that exposes process.env contents. This rule specifically targets the methods that trigger the vulnerability.
author: SCW Feed Engine (AI-generated)
date: 2026-05-07
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2026-42047/
tags:
- attack.credential_access
- attack.t1040
logsource:
category: webserver
detection:
selection:
cs-method:
- 'PATCH'
- 'OPTIONS'
- 'DELETE'
condition: selection
falsepositives:
- Legitimate administrative activity
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-42047 | Information Disclosure | Inngest versions 3.22.0 through 3.53.1 |
| CVE-2026-42047 | Information Disclosure | Vulnerable component: serve() HTTP handler |
| CVE-2026-42047 | Information Disclosure | Attack vector: PATCH, OPTIONS, or DELETE requests to serve() endpoint |
| CVE-2026-42047 | Information Disclosure | Affected configurations: Next.js Pages Router or Express's app.use(...) where serve() is reachable via PATCH, OPTIONS, or DELETE |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | May 08, 2026 at 00:16 UTC |
This content was AI-rewritten and enriched by Shimi's Cyber World based on the original source. All intellectual property rights remain with the original author.
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