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Response snapshot Oct 29, 2026, 02:31 UTC

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VulnerabilityCVE-2026-118668

LangGraph JavaScript custom authentication may permit cross-user Store access

LangGraph deployments using JavaScript or TypeScript custom authentication may fail to apply Store authorization changes returned by an authorization handler. In affected deployments, an authenticated user may be able to access Store data outside their authorized namespace.

At a glance

Exploited
Not known
Severity
8.6 High (CVSS 4.0)
Chance of exploitation
Not estimated
Sources
2 independent sources

What to do

GitHub lists first patched versions: langgraph-api: 0.15.0. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-4hm6-w6qq-w73v (opens a new tab)

What happened

Summary

LangGraph deployments using JavaScript or TypeScript custom authentication may fail to apply Store authorization changes returned by an authorization handler. In affected deployments, an authenticated user may be able to access Store data outside their authorized namespace.

Required conditions

A deployment is affected only when all of the following conditions apply:

Continue reading

- It uses an affected langgraph-api version. - It runs JavaScript or TypeScript custom authentication. - Its Store authorization handler relies on rewriting the requested namespace to restrict each user to their own data. - The attacker can authenticate as an ordinary user. - Multiple users' data is stored through the affected authorization path.

Python custom authentication handlers are not affected. JavaScript or TypeScript handlers that reject unauthorized namespace requests instead of rewriting them are also not affected.

The attack does not require administrator privileges, user interaction, a race condition, or the bypass of another mitigation.

Impact

An authenticated user may be able to read, overwrite, search, or delete Store data belonging to another user.

Patches

The issue is fixed in langgraph-api version 0.15.0. The server now carries changes made by a JavaScript or TypeScript authorization handler across the runtime boundary and applies them before performing the Store operation. It validates the resulting namespace after authorization and rejects the request if an authorization change is malformed or cannot be applied safely.

Users should upgrade to langgraph-api>=0.15.0.

Workarounds

Deployments that cannot upgrade immediately should change JavaScript or TypeScript Store authorization handlers to reject requests for unauthorized namespaces rather than relying on namespace rewriting.

This workaround must be applied to every Store action exposed by the deployment.

Affected package ranges reported by GitHub: langgraph-api: >= 0.1.2, < 0.15.0

Scores and how they were measured

CVSS base severity

8.6

Version 4.0As of

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-4hm6-w6qq-w73v (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-4hm6-w6qq-w73v, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE-2026-118668 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  4. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  5. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  6. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 28). LangGraph JavaScript custom authentication may permit cross-user Store access (CVE-2026-118668). https://kevwire.com/record/CVE-2026-118668

MLA

"LangGraph JavaScript custom authentication may permit cross-user Store access (CVE-2026-118668)." KEVWire, 28 Oct. 2026, kevwire.com/record/CVE-2026-118668.

Chicago

KEVWire. "LangGraph JavaScript custom authentication may permit cross-user Store access (CVE-2026-118668)." Last modified October 28, 2026. https://kevwire.com/record/CVE-2026-118668.

Evidence summary (plain text)

LangGraph JavaScript custom authentication may permit cross-user Store access (Oct 28, 2026).
LangGraph deployments using JavaScript or TypeScript custom authentication may fail to apply Store authorization changes returned by an authorization handler. In affected deployments, an authenticated user may be able to access Store data outside their authorized namespace.

A deployment is affected only when all of the following conditions apply:

- It uses an affected langgraph-api version.
- It runs JavaScript or TypeScript custom authentication.
- Its Store authorization handler relies on rewriting the requested namespace to restrict each user to their own data.
CVSS 8.6 (version 4.0; evidence as of Oct 28, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-118668).
Sources:
GitHub-reviewed advisory GHSA-4hm6-w6qq-w73v: https://github.com/advisories/GHSA-4hm6-w6qq-w73v
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc
NVD CVE-2026-118668: https://nvd.nist.gov/vuln/detail/CVE-2026-118668
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-28T21:10:57.957Z&lastModEndDate=2026-10-28T22:40:57.609Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-28T20:41:00.896Z&lastModEndDate=2026-10-28T22:10:55.656Z&resultsPerPage=500&startIndex=0
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-10-28T20:10:59.549Z&lastModEndDate=2026-10-28T21:40:57.581Z&resultsPerPage=500&startIndex=0
Record ID: CVE-2026-118668.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 29, 2026, 02:00 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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