LangChain: MongoDBChatMessageHistory query injection can allow cross-session access

[ Description ]Official description

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.

[ Fixes ]Fixes and patches

• @langchain/mongodb 1.3.1Fixed version · GitHub Advisories · npm package @langchain/mongodb: upgrade to 1.3.1 or later (affected <= 1.3.0)

[ Advisories ]Government CERT advisories

• BSI CERT-Bund6 Oct 2026WID-SEC-2026-3776

  LangChain: Multiple vulnerabilities Translated from German

  CVE-2026-106119CVE-2026-105799

[ Packages ]Affected open-source packages

• @langchain/mongodb npmAffected <= 1.3.0 · fixed in 1.3.1 · GHSA-m6rx-h84q-8r95

[ References ]References

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