CVE-2026-55253 LangChain MongoDB: NoSQL Operator Injection in MongoDBSaver.list() leading to cross-tenant data exposure
Authenticated attackers can inject MongoDB operators to bypass tenant isolation and access other tenants' data in multi-tenant deployments.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-55253?
CVE-2026-55253 is a high-severity SQL injection vulnerability in langchain-ai langchain-mongodb, published on 14 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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.
Weakness: CWE-943
Which versions are affected by CVE-2026-55253?
6 open source packages ship an affected version, including langgraph-checkpoint-mongodb and langgraph-store-mongodb.
| Package | Affected | Fixed in |
|---|---|---|
langgraph-checkpoint-mongodb PyPI | All versions | 0.3.0 |
langgraph-checkpoint-mongodb PyPI | All versions | 0.3.0 |
langgraph-checkpoint-mongodb PyPI | All versions | 0.3.0 |
langgraph-store-mongodb PyPI | All versions | 0.4.0 |
langgraph-store-mongodb PyPI | All versions | 0.4.0 |
langgraph-store-mongodb PyPI | All versions | 0.4.0 |
How do I fix CVE-2026-55253?
Upgrade langgraph-checkpoint-mongodb to 0.3.0 or later.
Use parameterised queries everywhere and never build SQL by joining strings. Upgrade affected software first; a web application firewall only buys time. More about SQL injection.
Is CVE-2026-55253 being exploited?
There is no known exploitation of CVE-2026-55253 in the wild and no public exploit code.
Sources
Also known as GHSA-533j-2v4q-mw5h, PYSEC-2026-3859, PYSEC-2026-3860, ROOT-APP-PYPI-CVE-2026-55253.