CVE-2026-41690

High

Published: 08 May 2026

Published

08 May 2026

Modified

12 May 2026

KEV Added

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Patch

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CVSS Score v3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L

EPSS Score 0.0031 22.8th percentile

Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-41690 is a high-severity Path Traversal (CWE-22) vulnerability. Its CVSS base score is 8.6 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 22.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2026-28792

Vulnerability details

18next-http-middleware is a middleware to be used with Node.js web frameworks like express or Fastify and also for Deno. Versions prior to 3.9.3 allow an unauthenticated HTTP client to pollute Object.prototype in the Node.js process hosting the middleware, via two…

unvalidated entry points that reach internal object-key writes: getResourcesHandler and missingKeyHandler. This can break authorisation checks (if (user.isAdmin) returning true for any user), cause type-confusion DoS, and depending on downstream code it can be chained into RCE.

CWE(s): CWE-22 CWE-1321

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1068 Exploitation for Privilege Escalation Privilege Escalation

Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.

attack.mitre.org →

Why these techniques?

Unauthenticated HTTP request to public-facing Node.js web middleware directly enables exploitation (T1190); prototype pollution breaks authorization logic and enables privilege escalation (T1068), with potential RCE chaining.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0