CVE-2026-40190
MEDIUM EPSS 14.1%
Published Apr 10, 20262mo ago · Modified Jun 17, 20262w ago
5.6 CVSS 3.1
Published Apr 10, 2026 2mo ago
Last Modified Jun 17, 2026 2w ago
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.
CVSS Details
Base Score
Exploitability
Impact
Vector string
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L Attack Vector Network
Attack Complexity High
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality Low
Integrity Low
Availability Low
Threat Intelligence
EPSS Exploit Probability
14.1% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available
Weaknesses 1
CWE-1321
References 1
- github.com https://github.com/langchain-ai/langsmith-sdk/security/advisories/GHSA-fw9q-39r9-c252
Remediation
No remediation data recorded yet
Check vendor advisories and the NVD entry for patch availability.