CVE-2025-68665

LangChain is a framework for building LLM-powered applications. Prior to @langchain/core versions 0.3.80 and 1.1.8, and prior to langchain versions 0.3.37 and 1.2.3, a serialization injection vulnerability exists in LangChain JS's toJSON() method (and subsequently when string-ifying objects using JSON.stringify(). The method did not escape objects with 'lc' keys when serializing free-form data in kwargs. The 'lc' key is used internally by LangChain to mark serialized objects. When user-controlled data contains this key structure, it is treated as a legitimate LangChain object during deserialization rather than plain user data. This issue has been patched in @langchain/core versions 0.3.80 and 1.1.8, and langchain versions 0.3.37 and 1.2.3

Affected products

Langchain-Core, Langchain

Langchain Langchain.js

< 0.3.37, 1.2.3

Langchain Langchain\/core

< 0.3.80, 1.1.8

Fix

Available

CVSS 3.1

9.1 CRITICAL

EPSS

0.8% (52th percentile)

Weakness

CWE-502

NVD status

Analyzed

Published

2025-12-23

No exploit for CVE-2025-68665 has been indexed yet. Our index is built from live traffic and upstream syncs, so this page can only say what it knows — not that no exploit exists.