langchain-ai langchain-mongodb filter code injection

Summaryinfo

A vulnerability categorized as problematic has been discovered in langchain-ai langchain-mongodb, langgraph-checkpoint-mongodb and langgraph-store-mongodb. Impacted is the function MongoDBSaver.list/MongoDBSaver.alist/MongoDBStore.search. Such manipulation of the argument filter leads to code injection. This vulnerability is listed as CVE-2026-55253. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability was found in langchain-ai langchain-mongodb, langgraph-checkpoint-mongodb and langgraph-store-mongodb (affected version unknown) and classified as problematic. Affected by this issue is the function MongoDBSaver.list/MongoDBSaver.alist/MongoDBStore.search. The manipulation of the argument filter with an unknown input leads to a code injection vulnerability. Using CWE to declare the problem leads to CWE-94. The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. Impacted is confidentiality. CVE summarizes:

LangChain MongoDB provides integrations between MongoDB, Atlas, LangChain, and LangGraph. Prior to langgraph-checkpoint-mongodb 0.3.0 and langgraph-store-mongodb 0.4.0, MongoDBSaver.list(), MongoDBSaver.alist(), and MongoDBStore.search() incorporate filter dictionaries into MongoDB queries without recursively rejecting keys prefixed with $. An authenticated caller who controls a filter argument through HTTP query parameters, request body fields, or agent tool arguments can inject MongoDB Query Language operators such as $regex or $where. In a multi-tenant deployment that uses the filter to enforce per-user or per-tenant isolation, injected operators can bypass intended equality filtering and expose other tenants' checkpoint or store data. Filters constructed entirely from trusted server-side values have lower practical risk. This issue is fixed in langgraph-checkpoint-mongodb 0.3.0 and langgraph-store-mongodb 0.4.0.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-55253 since 06/16/2026. The exploitation is known to be easy. The attack may be launched remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 09/14/2026). The MITRE ATT&CK project declares the attack technique as T1059.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Type

• Database Software

Vendor

• langchain-ai

Name

• langchain-mongodb
• langgraph-checkpoint-mongodb
• langgraph-store-mongodb

Website

• Product: https://github.com/langchain-ai/langchain-mongodb/

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