Vulnerability · Published Oct 6, 2026 · Assigned by GitHub_M
CVE-2026-106119LangChain: MongoDBChatMessageHistory query injection can allow cross-session access
Medium 6.0
In plain English
A medium-severity security flaw in mongodb from @langchain. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | @langchain/mongodb | 1.3.1 | GHSA-m6rx-h84q-8r95 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| langchain-ai | langchainjs | < 1.5.14 |
| @langchain | mongodb | < 1.3.1 |
Weakness: CWE-943 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N
References
- https://github.com/langchain-ai/langchainjs/security/advisories/GHSA-m6rx-h84q-8r95 x_refsource_CONFIRM
- https://github.com/langchain-ai/langchainjs/pull/11672 x_refsource_MISC
- https://github.com/langchain-ai/langchainjs/commit/946e3d856ff1f8ce7f7b9374c83f680a6ada79af x_refsource_MISC
- https://github.com/langchain-ai/langchainjs/releases/tag/@langchain/mongodb@1.3.1 x_refsource_MISC