VulnerabilityPublished 5 May 2026Updated 11 May 2026

CVE-2026-42047: Inngest TypeScript SDK exposes environment variables via serve() handler on unhandled HTTP methods

Affects inngestSource GCVE Database

Authoritative record:CVE-2026-42047· High 8.6

Not known to be exploited · CVSS 8.6 High : upgrade to 3.54.0 soon.

Data as of 27 Oct 2026, 00:07 UTC

CVSS 3.1 base score

8.6High

How severe the flaw is on the 0–10 CVSS scale.

Patch: Available – fixed in 3.54.0

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Changed
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 7 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade inngest to 3.54.0.

Affected software

Product	Affected	Fixed in
npminngest	Affected >=3.22.0 <3.54.0	Fixed in 3.54.0

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Description

# 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 `inngest` SDK version `>= 3.22.0, <= 3.53.1` (inclusive) - Its `serve()` endpoint is reachable via `PATCH`, `OPTIONS`, or `DELETE` requests. Please check your framework's implementation for the serve handler ([documentation](https://www.inngest.com/docs/learn/serving-inngest-functions)) 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 routes `PATCH` and `OPTIONS` to the handler by default. The following are **not** affected: - Next.js App Router handlers that explicitly export only `GET`, `POST`, and `PUT`. - Applications using the `connect` worker method. - SDK versions `< 3.22.0` and `>= 3.54.0`, including all `4.x` releases. The vulnerability was responsibly disclosed by an Inngest user. At this time, there are no known reports of exploitation. # Remediation 1. Upgrade to `inngest@3.54.0` or later. The fix is backwards compatible with the `3.x` release line. The `4.x` line is also unaffected. 2. Rotate any secrets that were presence in environment variables (`process.env`) within affected environments including Inngest signing keys and event keys 3. Search logs for any requests to your `serve` endpoints using the `PATCH`, `OPTIONS`, `DELETE` http 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](https://vercel.com/docs/deployment-protection#standard-protection)" and [the ability to delete older deployments](https://vercel.com/kb/guide/how-do-i-delete-an-individual-deployment) 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.

CWE-200Exposure of Sensitive Information to an Unauthorized Actor (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #20OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Separation of Privilege
Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area.
OWASP Cheat Sheets
Error Handling (opens in a new tab)
Logging (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.4 (opens in a new tab)
V14.3.3 (opens in a new tab)
V7.3.3 (opens in a new tab)
Attack patterns
Subverting Environment Variable Values (opens in a new tab)
ICMP Echo Request Ping (opens in a new tab)
TCP SYN Scan (opens in a new tab)
Enumerate Mail Exchange (MX) Records (opens in a new tab)
DNS Zone Transfers (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-497Exposure of Sensitive System Information to an Unauthorized Control Sphere (opens in a new tab)
Base weaknessOWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product does not properly prevent sensitive system-level information from being accessed by unauthorized actors who do not have the same level of access to the underlying system as the product does.
Architecture and Design · Implementation
Production applications should never use methods that generate internal details such as stack traces and error messages unless that information is directly committed to a log that is not viewable by the end user.
OWASP Cheat Sheets
Error Handling (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V14.3.2 (opens in a new tab)
V8.3.4 (opens in a new tab)
V14.3.3 (opens in a new tab)
Attack patterns
Web Application Fingerprinting (opens in a new tab)
System Location Discovery (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

WeaknessesCWE-200, CWE-497

Technical details

References

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