CVE-2026-55253

HIGHPre-NVD 7.77.7
EchelonGraph scoreLOW confidence

This high-severity CVE scores 7.7 under the CNA's CVSS (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: cna:github_m
7.7EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 7.7Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

LangChain MongoDB has NoSQL Operator Injection in MongoDBSaver.list() leading to cross-tenant data exposure

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:

  • Your application uses langgraph-checkpoint-mongodb or langgraph-store-mongodb.
  • Your application calls MongoDBSaver.list(), MongoDBSaver.alist(), or
MongoDBStore.search() with a filter argument.
  • Any part of that filter argument is derived from user-controlled input — for example, HTTP
query parameters, request body fields, or agent tool arguments.
  • 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 |

CVSS v3
7.7
EG Score
7.7(low)
EG Risk
39(Track)
EG Risk 39/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity77% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
—
EPSS %ILE
—
KEV
Not listed

Published

August 20, 2026

Last Modified

August 20, 2026

Vendor Advisories for CVE-2026-55253(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Data Freshness Timeline

(refreshed 1× in last 7d / 1× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-08-20 17:42 UTCEG score recompute

Frequently asked(4)

What is CVE-2026-55253?
CVE-2026-55253 is a high vulnerability published on August 20, 2026. LangChain MongoDB has NoSQL Operator Injection in MongoDBSaver.list() leading to cross-tenant data exposure 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…
When was CVE-2026-55253 disclosed?
CVE-2026-55253 was first published in the National Vulnerability Database on August 20, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-55253?
CVE-2026-55253 has a CVSS v4.0 base score of 7.7 (CNA self-assessment; NVD's own analysis pending). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-55253?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55253, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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