CVE-2026-106119

LangChain: MongoDBChatMessageHistory query injection can allow cross-session access

MEDIUM
6
CVSS Score
Published: October 6, 2026 at 06:01 PM UTC
Updated: October 6, 2026 at 08:17 PM UTC
2 products affected across 2 vendorsLangchainjsMongoDB

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Severity
MEDIUM6
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

6MEDIUMGitHub_M
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-943

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