CVE-2025-68665 Details

A serialization injection vulnerability has been identified in LangChain JS, specifically in the `toJSON()` method. This issue affects versions of LangChain prior to 0.3.80 and 1.2.3, as well as @langchain/core versions prior to 1.1.8. The vulnerability arises because the `toJSON()` method did not properly escape objects containing 'lc' keys when serializing free-form data in keyword arguments. The 'lc' key is used internally by LangChain to identify serialized objects. As a result, user-controlled data with this key structure could be misinterpreted as a legitimate LangChain object during deserialization, rather than as plain user data.

Users can update to LangChain versions 1.2.3 or later, or @langchain/core versions 1.1.8 or later, to address this vulnerability. After updating, be cautious with the 'secretsFromEnv' option, which now defaults to false. If needed, secrets can be loaded from environment variables or specified through the 'secretsMap' option.