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Response snapshot Oct 29, 2026, 01:26 UTC

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VulnerabilityCVE-2026-55236

langgraph-api: Incomplete assistant authorization in LangGraph Server run creation

In affected versions of langgraph-api (the LangGraph Server runtime), the run-creation path authorized the assistant attached to a run using a different authorization event than the rest of the assistant-handling code paths. Direct assistant reads and cron creation dispatch the assistants.

At a glance

Exploited
Not known
Severity
5.9 Medium (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

GitHub lists first patched versions: langgraph-api: 0.10.0. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-jfj5-wrj9-63x4 (opens a new tab)

What happened

Summary

In affected versions of langgraph-api (the LangGraph Server runtime), the run-creation path authorized the assistant attached to a run using a different authorization event than the rest of the assistant-handling code paths. Direct assistant reads and cron creation dispatch the assistants.read authorization event; run creation dispatched assistants.search with an incomplete value.

In deployments whose custom authorization handlers register only an assistants.read handler (without an assistants.search handler and without a global fallback handler), no handler was consulted on the run-creation path, the returned filter set was empty, and the owner constraint was omitted from the resulting query.

As a result, in those deployments a request to create a run could reference a private assistant owned by another user, even where direct assistant reads, assistant search, and cron creation against that assistant were correctly denied. The run-creation response merged the referenced assistant's metadata, config, and context into fields returned to the requesting user. These fields can carry sensitive configuration; the runtime encrypts them at rest for that reason.

Continue reading

We have no evidence of this behavior occurring in the wild.

Affected users / systems

You may be affected if you:

- run langgraph-api (the LangGraph Server / Agent Server runtime, including via the LangGraph Platform Helm chart), and - use custom authorization handlers that gate assistant access through an assistants.read or assistants.search handler rather than a global handler covering all assistant events.

Deployments without custom authorization handlers, or whose handlers apply an equivalent owner filter across all assistant events (for example through a global handler), are not affected.

Impact

- Confidentiality: exposure of another user's private assistant metadata, config, and context through the run-creation response. These fields can contain sensitive configuration. - Integrity: creation of a run associated with another user's private assistant, beyond the requesting user's authorization scope; the run is then carried out using that assistant's configuration.

Patches / mitigation

Run creation, and the parallel cron-creation path, now dispatch the assistants.read authorization event in both the in-memory and gRPC/Postgres runtimes, matching direct assistant reads. Client-supplied run and cron metadata is no longer forwarded into that authorization event, so handlers receive a consistent value shape and determine access by returning an owner filter that is applied server-side. Fixed in langgraph-api 0.10.0.

This is a behavioral change for deployments with custom authorization handlers:

- Handlers that gated assistant access only through assistants.search during run creation are no longer consulted on that path; provide an equivalent assistants.read handler that returns the same owner filter. - The metadata field on the assistants.read event during run and cron creation is no longer populated; handlers that read or stamped it should move that logic into the run/cron create handlers.

Operational guidance

- Register an assistants.read handler (or a global handler covering it) that returns an owner-style filter, and confirm parity across the assistant read, search, and run/cron creation paths. - Upgrade to a release containing this change.

Affected package ranges reported by GitHub: langgraph-api: < 0.10.0

Scores and how they were measured

CVSS base severity

5.9

Version 3.1As of

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N

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-jfj5-wrj9-63x4 (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-jfj5-wrj9-63x4, its actual identifiers, source dates, and structured metrics.

    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-api: Incomplete assistant authorization in LangGraph Server run creation (CVE-2026-55236). https://kevwire.com/record/CVE-2026-55236

MLA

"langgraph-api: Incomplete assistant authorization in LangGraph Server run creation (CVE-2026-55236)." KEVWire, 28 Oct. 2026, kevwire.com/record/CVE-2026-55236.

Chicago

KEVWire. "langgraph-api: Incomplete assistant authorization in LangGraph Server run creation (CVE-2026-55236)." Last modified October 28, 2026. https://kevwire.com/record/CVE-2026-55236.

Evidence summary (plain text)

langgraph-api: Incomplete assistant authorization in LangGraph Server run creation (Aug 19, 2026).
In affected versions of langgraph-api (the LangGraph Server runtime), the run-creation path authorized the assistant attached to a run using a different authorization event than the rest of the assistant-handling code paths. Direct assistant reads and cron creation dispatch the assistants.read authorization event; run creation dispatched assistants.search with an incomplete value.
CVSS 5.9 (version 3.1; evidence as of Oct 28, 2026; https://github.com/advisories/GHSA-jfj5-wrj9-63x4).
Sources:
GitHub-reviewed advisory GHSA-jfj5-wrj9-63x4: https://github.com/advisories/GHSA-jfj5-wrj9-63x4
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc
Record ID: CVE-2026-55236.
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, 00:55 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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