CVE-2026-45134: Langchain-Ai Langsmith-SDK

High severity, CVSS 7.1. EPSS: 0.3% chance of exploitation in the next 30 days.

LangSmith Client SDKs provide SDK's for interacting with the LangSmith platform. Prior to LangSmith SDK Python 0.8.0 and JS/TS 0.6.0, the LangSmith SDK's prompt pull methods (pull_prompt / pull_prompt_commit in Python, pullPrompt / pullPromptCommit in JS/TS) fetch and deserialize prompt manifests from the LangSmith Hub. These manifests may contain serialized LangChain objects and model configuration that affect runtime behavior. When pulling a public prompt by owner/name identifier, the manifest content is controlled by an external party, but prior versions of the SDK did not distinguish this from pulling a prompt within the caller's own organization. This vulnerability is fixed in LangSmith SDK Python 0.8.0 and JS/TS 0.6.0.

Affected products

• Langchain-Ai Langsmith-SDK: before 0.8.0 (fixed in 0.8.0); before 0.6.0 (fixed in 0.6.0)

Published 2026-05-27. Last modified 2026-06-17.