langchain-ai langgraph-api up to 0.9.x Authentication Middleware improper authentication

Summaryinfo

A vulnerability was found in langchain-ai langgraph-api up to 0.9.x and classified as critical. The affected element is an unknown function of the component Authentication Middleware. The manipulation results in improper authentication. This vulnerability is identified as CVE-2026-55235. The attack can be executed remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical has been found in langchain-ai langgraph-api up to 0.9.x. Affected is an unknown code of the component Authentication Middleware. The manipulation with an unknown input leads to a improper authentication vulnerability. CWE is classifying the issue as CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

langgraph-api implements the LangGraph API for rapid development and testing. Prior to 0.10.0, langgraph-api permits a run or cron to specify a relative webhook target that is delivered through an in-process loopback transport, and the authentication middleware treats that transport as internal without applying the authentication context used for external requests. In deployments that rely on per-user authorization to separate threads and runs, an authenticated user can direct a webhook to the server's own thread and run routes, allowing creation of a run on or modification of another user's thread and limited incorporation of the targeted thread's metadata into the created run record. The affected path requires webhook targets and per-user authorization boundaries; deployments that deliberately re-enable loopback delivery should restrict it to controlled same-process routes because those webhooks remain unauthenticated. This issue is fixed in version 0.10.0.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-55235 since 06/16/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. There are neither technical details nor an exploit publicly available.

Upgrading to version 0.10.0 eliminates this vulnerability.

Once again VulDB remains the best source for vulnerability data.

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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