CVE-2026-48121

Name of the Vulnerable Software and Affected Versions @langchain/langgraph-checkpoint-mongodb versions prior to 1.3.1

Description A NoSQL injection issue exists in the MongoDBSaver.getTuple() function. The software fails to enforce type validation for checkpoint identifiers passed via config.configurable, specifically the thread id, checkpoint ns, and checkpoint id variables. If an attacker provides an object containing MongoDB operators (such as $gt or $ne) instead of a string, the system interprets these as query operators. This allows an attacker to bypass thread scoping and leak sensitive data, including checkpoint state, metadata, and pending writes, across different tenants. This risk is primarily present in multi-tenant or user-isolated environments where untrusted input is forwarded into the configuration without string coercion or schema validation.

Recommendations Update @langchain/langgraph-checkpoint-mongodb to version 1.3.1 or later. Validate identifier fields at API boundaries to ensure they are strings and avoid passing raw client objects into the graph configuration.