Deserialization in Langchain Langchain\/core
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
Vulnerability class: Insecure Deserialization
EPSS: 0.008 (51.5th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N.
Affected products
- Langchain Langchain\/core
- Langchain Langchain.js
- Langchain-ai Langchainjs — versions @langchain/core >= 1.0.0, < 1.1.8, @langchain/core < 0.3.80, langchain >= 1.0.0, < 1.2.3
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2025-68665?
- CVE-2025-68665 is a high-severity vulnerability in Langchain Langchain\/core, classified under Deserialization of Untrusted Data. CVSS score: 8.6/10. Published 2025-12-23.
- How severe is CVE-2025-68665?
- High severity. CVSS v3 base score is 8.6 out of 10.