CVE-2026-40190

Name: CVE-2026-40190
Creator: NVD / NIST
Published: 2026-04-10T20:16:24.043+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.6/10EPSS 0.23%

Last modified Jun 17, 2026

This CVE is reserved or awaiting analysis. Details will appear once published by NVD.

Description

LangSmith Client SDKs provide SDK's for interacting with the LangSmith platform. Prior to 0.5.18, the LangSmith JavaScript/TypeScript SDK (langsmith) contains an incomplete prototype pollution fix in its internally vendored lodash set() utility. The baseAssignValue() function only guards against the __proto__ key, but fails to prevent traversal via constructor.prototype. This allows an attacker who controls keys in data processed by the createAnonymizer() API to pollute Object.prototype, affecting all objects in the Node.js process. This vulnerability is fixed in 0.5.18.

Metrics

CVSS 3.1

5.6/10

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

EPSS Probability

0.23%

14.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-1321

References

https://github.com/langchain-ai/langsmith-sdk/security/advisories/GHSA-fw9q-39r9-c252

Timeline

Published: Apr 10, 2026
Last Modified: Jun 17, 2026
Status: Awaiting Analysis

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Source: NVD / NIST