CVE-2025-68665 Langchain — Exploit & Vulnerability Details CRITICAL

Parameter	Value
CVSS	9.1 (CRITICAL)
Affected Versions	1.0.0 — 1.2.3
Fixed In	0.3.37
Type	CWE-502 (Deserialization of Untrusted Data)
Vendor	Langchain
Public PoC	No

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

Attack Parameters

Attack Vector

Network

Can be exploited remotely

Attack Complexity

Low

Easy to exploit

Privileges Required

None

No privileges needed

User Interaction

None

No user interaction needed

Impact Assessment

Confidentiality

High

Complete data leak

Integrity

High

Complete data modification

Availability

None

No disruption

CVSS Vector v3.1

Weakness Type (CWE)

CWE-502 Deserialization of Untrusted Data

Vulnerable Products 4

Configuration	From (including)	Up to (excluding)
Langchain Langchain.Js cpe:2.3:a:langchain:langchain.js::::::::	—	`0.3.37`
Langchain Langchain.Js cpe:2.3:a:langchain:langchain.js::::::::	`1.0.0`	`1.2.3`
Langchain Langchain\/Core cpe:2.3:a:langchain:langchain\/core::::::node.js::*	—	`0.3.80`
Langchain Langchain\/Core cpe:2.3:a:langchain:langchain\/core::::::node.js::*	`1.0.0`	`1.1.8`