Vulnerability details

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

• https://github.com/langchain-ai/langchainjs/commit/e5063f9c6e9989ea067dfdff39262b9e7b6aba62 x_refsource_MISC
• https://github.com/langchain-ai/langchainjs/releases/tag/%40langchain%2Fcore%401.1.8 x_refsource_MISC
• https://github.com/langchain-ai/langchainjs/releases/tag/langchain%401.2.3 x_refsource_MISC
• https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-r399-636x-v7f6 x_refsource_CONFIRM