CVE-2026-55253

CVE-2026-55253 is a high-severity security vulnerability in langgraph-checkpoint-mongodb (pip), affecting versions < 0.3.0. It is fixed in 0.3.0, 0.4.0.

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Summary

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:

  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

Impact

CVE-2026-55253 has a CVSS score of 7.7 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.3.0, 0.4.0); upgrading removes the vulnerable code path.

Affected versions

langgraph-checkpoint-mongodb (< 0.3.0) langgraph-store-mongodb (< 0.4.0)

Security releases

langgraph-checkpoint-mongodb → 0.3.0 (pip) langgraph-store-mongodb → 0.4.0 (pip)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

Upgrade the following packages to resolve this vulnerability:

langgraph-checkpoint-mongodb to 0.3.0 or later; langgraph-store-mongodb to 0.4.0 or later

Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.

Frequently Asked Questions

  1. What is CVE-2026-55253? CVE-2026-55253 is a high-severity security vulnerability in langgraph-checkpoint-mongodb (pip), affecting versions < 0.3.0. It is fixed in 0.3.0, 0.4.0.
  2. How severe is CVE-2026-55253? CVE-2026-55253 has a CVSS score of 7.7 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
  3. Which packages are affected by CVE-2026-55253?
    • langgraph-checkpoint-mongodb (pip) (versions < 0.3.0)
    • langgraph-store-mongodb (pip) (versions < 0.4.0)
  4. Is there a fix for CVE-2026-55253? Yes. CVE-2026-55253 is fixed in 0.3.0, 0.4.0. Upgrade to this version or later.
  5. Is CVE-2026-55253 exploitable, and should I be worried? Whether CVE-2026-55253 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
  6. What actually determines whether CVE-2026-55253 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
  7. How do I fix CVE-2026-55253?
    • Upgrade langgraph-checkpoint-mongodb to 0.3.0 or later
    • Upgrade langgraph-store-mongodb to 0.4.0 or later

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