langchain-ai langgraph-api up to 0.9.x Run-Creation improper authorization

Summaryinfo

A vulnerability has been found in langchain-ai langgraph-api up to 0.9.x and classified as critical. Impacted is an unknown function of the component Run-Creation. The manipulation leads to improper authorization. This vulnerability is referenced as CVE-2026-55236. Remote exploitation of the attack is possible. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in langchain-ai langgraph-api up to 0.9.x. It has been rated as critical. This issue affects an unknown part of the component Run-Creation. The manipulation with an unknown input leads to a improper authorization vulnerability. Using CWE to declare the problem leads to CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

langgraph-api implements the LangGraph API for rapid development and testing. Prior to 0.10.0, the langgraph-api run-creation path authorizes the assistant attached to a run by dispatching assistants.search with an incomplete value instead of the assistants.read event used by direct reads and cron creation. In deployments with custom resource handlers that register only assistants.read, omit an assistants.search handler, and have no global fallback handler, no applicable handler supplies an owner filter, allowing a low-privileged user to reference another user's private assistant through POST /runs or POST /threads/{thread_id}/runs. The run-creation response can disclose the private assistant's metadata, config, and context, and the run can execute using that assistant's configuration. Deployments without custom authorization handlers, or with an equivalent owner filter applied through a global handler or across all assistant events, are not affected. This issue is fixed in version 0.10.0.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-55236 since 06/16/2026. The exploitation is known to be easy. The attack may be initiated remotely. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1548.002 according to MITRE ATT&CK.

Upgrading to version 0.10.0 eliminates this vulnerability.

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Productinfo

Type

• Automation Software

Vendor

• langchain-ai

Name

• langgraph-api

Version

• 0.1
• 0.2
• 0.3
• 0.4
• 0.5
• 0.6
• 0.7
• 0.8
• 0.9

CPE 2.3info

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CPE 2.2info

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