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High severityOSV Advisory· Published Dec 23, 2025· Updated Dec 24, 2025

LangChain serialization injection vulnerability enables secret extraction

CVE-2025-68665

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

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

Affected packages

Versions sourced from the GitHub Security Advisory.

PackageAffected versionsPatched versions
@langchain/corenpm
>= 1.0.0, < 1.1.81.1.8
@langchain/corenpm
< 0.3.800.3.80
langchainnpm
>= 1.0.0, < 1.2.31.2.3
langchainnpm
< 0.3.370.3.37

Affected products

29

Patches

Vulnerability mechanics

References

6

News mentions

0

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