CVE-2026-45134
LangSmith SDK: Public prompt pull deserializes untrusted manifests without trust boundary warning
Impact
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 packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | langsmith | < 0.8.0 | 0.8.0 |
| npm | langsmith | < 0.6.0 | 0.6.0 |
| pip | langchain-classic | < 1.0.7 | 1.0.7 |
| pip | langchain | < 0.3.30 | 0.3.30 |