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PYSEC-2026-3858

Vulnerability from pysec - Published: 2026-09-10 09:44 - Updated: 2026-09-10 11:02
VLAI
Details

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.

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.
Severity
5.9 (Medium)
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N
Impacted products
Name purl
langgraph-api pkg:pypi/langgraph-api
Aliases
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "langgraph-api",
        "purl": "pkg:pypi/langgraph-api"
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      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.10.0"
            }
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          "type": "ECOSYSTEM"
        }
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    }
  ],
  "aliases": [
    "CVE-2026-55236",
    "GHSA-jfj5-wrj9-63x4"
  ],
  "details": "## Summary\n\nIn 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.\n\nAs 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\u0027s `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.\n\nWe have no evidence of this behavior occurring in the wild.\n\n## Affected users / systems\n\nYou may be affected if you:\n\n- run `langgraph-api` (the LangGraph Server / Agent Server runtime, including via the LangGraph Platform Helm chart), and\n- 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.\n\nDeployments 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.\n\n## Impact\n\n- Confidentiality: exposure of another user\u0027s private assistant `metadata`, `config`, and `context` through the run-creation response. These fields can contain sensitive configuration.\n- Integrity: creation of a run associated with another user\u0027s private assistant, beyond the requesting user\u0027s authorization scope; the run is then carried out using that assistant\u0027s configuration.\n\n## Patches / mitigation\n\nRun 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.\n\nThis is a behavioral change for deployments with custom authorization handlers:\n\n- 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.\n- 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.\n\n## Operational guidance\n\n- 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.\n- Upgrade to a release containing this change.",
  "id": "PYSEC-2026-3858",
  "modified": "2026-09-10T11:02:12.014480Z",
  "published": "2026-09-10T09:44:51.663830Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/langchain-ai/helm/security/advisories/GHSA-jfj5-wrj9-63x4"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/langchain-ai/helm"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/langgraph-api"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-jfj5-wrj9-63x4"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-55236"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "langgraph-api: Incomplete assistant authorization in LangGraph Server run creation"
}



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