SecuriTricks - CVE-2026-40190

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.

Product(s) Impacted

Vendor	Product	Versions
Langsmith	Langsmith	*
Lodash	Lodash	*
Node.js	Node.js	*

Weaknesses

Common security weaknesses mapped to this vulnerability.

CWE-1321

Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.

*CPE(s)

Affected systems and software identified for this CVE.

Type	Vendor	Product	Version	Update	Edition	Language	Software Edition	Target Software	Target Hardware	Other Information
a	langsmith	langsmith	/	/	/	/	/	/	/	/
a	lodash	lodash	/	/	/	/	/	/	/	/
a	node.js	node.js	/	/	/	/	/	/	/	/

References

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

CVSS Score

5.6 / 10

CVSS Data - 3.1

Attack Vector: NETWORK
Attack Complexity: HIGH
Privileges Required: NONE
Scope: UNCHANGED
Confidentiality Impact: LOW
Integrity Impact: LOW
Availability Impact: LOW

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

View Vector String

Timeline

Published: April 10, 2026, 8:16 p.m.
Last Modified: April 10, 2026, 8:16 p.m.

Status : Received

CVE has been recently published to the CVE List and has been received by the NVD.

More info

Source

[email protected]

CVE-2026-40190