| Component | LangChain |
| Severity | high (CVSS 8.6) |
| CVSS vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N |
| Published (NVD) | 2025-12-23 |
| Last modified | 2026-06-17 |
| Affected versions | langchain.js < 0.3.37 langchain.js >= 1.0.0, < 1.2.3 langchain\/core < 0.3.80 langchain\/core >= 1.0.0, < 1.1.8 |
| Fixed in | 0.3.37, 1.2.3, 0.3.80, 1.1.8 |
| Weakness | CWE-502 |
| CISA KEV | not listed |
NVD 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
What to do
- Upgrade LangChain to
0.3.37or later (or the patched release of your branch: 1.2.3, 0.3.80, 1.1.8). - Do not expose the component's API or UI to the internet without authentication in front of it.
Sources
- NVD: CVE-2025-68665
- https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-r399-636x-v7f6
- https://github.com/langchain-ai/langchainjs/commit/e5063f9c6e9989ea067dfdff39262b9e7b6aba62
- 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
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