CVE-2026-40190
CVE-2026-40190 · LangSmith Client SDKs has Prototype Pollution in langsmith-sdk via Incomplete `__proto__` Guard in Internal lodash `set()`
This page contains facts from public vulnerability sources. Check the original advisory before updating.
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 5.6 · Medium · EPSS 0.3% · Fix available
- Published
- Updated
Stack: node
Affected products and versions
langsmith-sdk
- Versions
- < 0.5.18: Affected
No fix published
langsmith npm
- Affected ranges
- SEMVER: < 0.5.18
Update to 0.5.18