Medium · CVSS 6.0CVE-2026-106119

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

Answer in brief

CVE-2026-106119 records a Medium severity (CVSS 6.0) vulnerability in LangChain: MongoDBChatMessageHistory query injection can allow cross-session access. The current sources do not mark it as known exploited. The current feed maps langchain-ai/langchainjs (generic), @langchain/mongodb (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 6, 2026Updated Oct 6, 2026Source checked Oct 6, 2026First seen by HOL Oct 6, 2026Material review Oct 6, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 6.0
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 6.0. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps langchain-ai/langchainjs (generic), @langchain/mongodb (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
langchain-ai/langchainjsgeneric	<1.5.14	1.5.14
@langchain/mongodbgeneric	<1.3.1	1.3.1

Recommended response

Check inventory. Check lockfiles and deployed manifests for langchain-ai/langchainjs, @langchain/mongodb.
Review the reported fix. Update langchain-ai/langchainjs to 1.5.14; @langchain/mongodb to 1.3.1 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Oct 6, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 6, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 6, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.