CVE-2026-55253

# Executive Summary A NoSQL injection issue exists in the langgraph-checkpoint-mongodb and langgraph-store-mongodb libraries. MongoDBSaver.list() and MongoDBStore.search() methods accept a filter parameter that is incorporated into MongoDB queries without sufficient validation. Because MongoDB query operator keys (those prefixed with $) are not rejected during filter construction, a caller with control of the filter input can embed MongoDB query operators directly into the query. --- ## CVSS Details ### CVSS 4.0 | Field | Value | |---|---| | **CVSS Version** | 4.0 | | **Vector String** | `CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N` | | **Base Score** | **7.1 (High)** | | Metric | Value | Rationale | |---|---|---| | Attack Vector (AV) | Network | Triggerable remotely via API | | Attack Complexity (AC) | Low | No special conditions required | | Attack Requirements (AT) | None | No prerequisite deployment or execution conditions | | Privileges Required (PR) | Low | Authenticated caller of the checkpoint/store API | | User Interaction (UI) | None | No user action required | | Vulnerable System Confidentiality (VC) | None | No direct impact on the vulnerable component itself | | Vulnerable System Integrity (VI) | None | Read-only access | | Vulnerable System Availability (VA) | None | No service disruption | | Subsequent System Confidentiality (SC) | High | Full access to other tenants' checkpoint data | | Subsequent System Integrity (SI) | None | No write or modification capability | | Subsequent System Availability (SA) | None | No service disruption to downstream systems | ### CVSS 3.1 | Field | Value | |---|---| | **CVSS Version** | 3.1 | | **Vector String** | `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N` | | **Base Score** | **7.7 (High)** | | Metric | Value | Rationale | |---|---|---| | Attack Vector | Network | Triggerable remotely via API | | Attack Complexity | Low | No special conditions required | | Privileges Required | Low | Authenticated caller of the checkpoint/store API | | User Interaction | None | No user action required | | Scope | Changed | Impact crosses tenant boundaries | | Confidentiality | High | Full access to other tenants' checkpoint data | | Integrity | None | Read-only access | | Availability | None | No service disruption | --- ## Affected Packages | Package | Distribution | Affected Methods | Affected Versions | |---|---|---|---| | `langgraph-checkpoint-mongodb` | PyPI | `MongoDBSaver.list()`, `MongoDBSaver.alist()` | < 0.3.0 | | `langgraph-store-mongodb` | PyPI | `MongoDBStore.search()` | < 0.4.0 | --- ## Advisory FAQ ### How do I know if I am affected? You are likely affected if **all** of the following are true: 1. Your application uses `langgraph-checkpoint-mongodb` or `langgraph-store-mongodb`. 2. Your application calls `MongoDBSaver.list()`, `MongoDBSaver.alist()`, or `MongoDBStore.search()` with a `filter` argument. 3. Any part of that `filter` argument is derived from user-controlled input — for example, HTTP query parameters, request body fields, or agent tool arguments. 4. You operate in a multi-tenant context where the `filter` is used to enforce per-user or per-tenant data isolation. If the `filter` argument is constructed entirely from trusted, server-side values, the practical risk is lower, but upgrading is still recommended. ### How do I fix the issue? **Upgrade** to the version of `langgraph-checkpoint-mongodb` and `langgraph-store-mongodb`. If you cannot upgrade immediately, apply the following mitigation: in your application code, before passing any user-controlled input to the `filter` parameter, remove or escape MongoDB Query metacharacters such as “$”. --- ## Acknowledgements Thanks to Kenichi Kawaguchi for responsibly disclosing this issue via the GitHub Security Advisory program on the langchain-mongodb repository. --- ## Revisions | Date | Description | |---|---| | 2026-06-05 | Initial advisory published |

No confirmed active exploitation of CVE-2026-55253 has been reported, but organizations should still patch proactively.

Update to patched version: LangGraph 0.3.0, LangGraph 0.4.0.

CVE-2026-55253 has a CVSS v3.1 base score of 7.7 (HIGH).