Answer in brief
CVE-2026-40190 records a Medium severity (CVSS 5.6) vulnerability in LangSmith Client SDKs has Prototype Pollution in langsmith-sdk via Incomplete `__proto__` Guard in Internal lodash `set()`. The current sources do not mark it as known exploited. The current feed maps langchain-ai/langsmith-sdk (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.6. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps langchain-ai/langsmith-sdk (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| langchain-ai/langsmith-sdkgeneric | < 0.5.18 | Not reported |
Published upstream
Apr 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 7, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 7, 2026
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.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2026-40190 records a Medium severity (CVSS 5.6) vulnerability in LangSmith Client SDKs has Prototype Pollution in langsmith-sdk via Incomplete `__proto__` Guard in Internal lodash `set()`. The current sources do not mark it as known exploited. The current feed maps langchain-ai/langsmith-sdk (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.6. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps langchain-ai/langsmith-sdk (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| langchain-ai/langsmith-sdkgeneric | < 0.5.18 | Not reported |
Published upstream
Apr 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jul 7, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 7, 2026
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.
Quoted source text, attributed separately from HOL analysis.