What’s Vulnerable › Vulnerabilities

CVE-2026-106119: LangChain: MongoDBChatMessageHistory query injection can allow cross-session access

• Severity: medium (CVSS 6.0 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-06 · updated 2026-10-06
• Weakness: CWE-943

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 products

• langchain-ai langchainjs: before 1.5.14
• @langchain mongodb: before 1.3.1

References

• 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

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