CVE-2025-68665: langchain.js Insecure Deserialization

Description

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

Is your site exposed to CVE-2025-68665?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

8.6

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Weakness Type (CWE)

CWE-502 Deserialization of Untrusted Data

Affected Products

Vendor	Product	Versions
langchain	langchain.js	< 0.3.37
langchain	langchain.js	1.0.0 — 1.2.3
langchain	langchain\/core	< 0.3.80
langchain	langchain\/core	1.0.0 — 1.1.8

References

Advisories & Patches

https://github.com/langchain-ai/langchainjs/commit/e5063f9c6e9989ea067dfdff39262b9e7b6aba62 https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-r399-636x-v7f6 https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-r399-636x-v7f6

Other References

https://github.com/langchain-ai/langchainjs/releases/tag/%40langchain%2Fcore%401.1.8 https://github.com/langchain-ai/langchainjs/releases/tag/langchain%401.2.3

Frequently Asked Questions

What is 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 It has a CVSS v3.1 base score of 8.6 (HIGH).

How severe is CVE-2025-68665? +

CVE-2025-68665 has a CVSS v3.1 score of 8.6 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-68665? +

CVE-2025-68665 affects products from langchain, specifically: langchain.js, langchain\/core. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-68665? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-10748

An authenticated user with the nx-licensing-create privilege can upload a specially crafted license file to execute arbitrary operating system commands …

CVE-2026-12569

A critical remote code execution (RCE) vulnerability has been reported in PTC Windchill PDMlink and PTC FlexPLM. The vulnerability may …

CVE-2026-44126

SEPPmail Secure Email Gateway before version 15.0.4 insecurely deserializes untrusted data, which can be reached from the new GINA UI …

CVE-2026-11857

Quanos SCHEMA ST4 on-premises contains a local privilege escalation vulnerability in the Client Update Service due to insecure deserialization in …

CVE-2026-47161

RELATE is a web-based courseware package. Prior to commit d66ba5659b459bf1ba56b7109b5f9ecf197cbefb, RELATE LMS configures its Celery workers to accept and deserialize …

CVE-2025-1077

A security vulnerability has been identified in the IBL Software Engineering Visual Weather and derived products (NAMIS, Aero Weather, Satellite …

CVE-2025-68665