CVE-2026-106119

LangChain is a framework for building LLM-powered applications. Prior to 1.3.1, MongoDBChatMessageHistory does not enforce the documented string type for an untrusted structured session identifier at runtime, allowing the identifier to be interpreted as a MongoDB query condition rather than as a literal value when multiple users' histories are stored in a shared MongoDB collection. An attacker able to invoke chat-history operations can read, modify, or delete another user's stored conversation. Applications using authenticated, server-controlled string identifiers are not affected. This issue is fixed in version 1.3.1.

• https://github.com/langchain-ai/langchainjs/commit/946e3d856ff1f8ce7f7b9374c83f680a6ada79af
• https://github.com/langchain-ai/langchainjs/pull/11672
• https://github.com/langchain-ai/langchainjs/releases/tag/@langchain/mongodb@1.3.1
• https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-m6rx-h84q-8r95