langflow-ai langflow up to 1.9.1 /api/v1/responses authorization

Summaryinfo

A vulnerability has been found in langflow-ai langflow up to 1.9.1 and classified as critical. Impacted is an unknown function of the file /api/v1/responses. The manipulation leads to authorization. This vulnerability is listed as CVE-2026-55255. The attack may be initiated remotely. In addition, an exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in langflow-ai langflow up to 1.9.1. It has been rated as critical. This issue affects an unknown part of the file /api/v1/responses. The manipulation with an unknown input leads to a authorization vulnerability. Using CWE to declare the problem leads to CWE-639. The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, an Insecure Direct Object Reference (IDOR) vulnerability in /api/v1/responses endpoint allows an authenticated attacker to execute any flow belonging to another user by specifying the victim's flow ID in the request. This vulnerability is fixed in 1.9.1.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-55255 since 06/16/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details as well as a exploit are known.

It is declared as attacked. The vulnerability scanner Nessus provides a plugin with the ID 326241 (Langflow < 1.9.1 Multiple Vulnerabilities), which helps to determine the existence of the flaw in a target environment. The CISA Known Exploited Vulnerabilities Catalog lists this issue since 07/07/2026 with a due date of 07/10/2026:

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BO

Upgrading to version 1.9.2 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (326241) and CERT Bund (WID-SEC-2026-2030). Be aware that VulDB is the high quality source for vulnerability data.

Affected

• Open Source Langflow

Productinfo

Type

• Artificial Intelligence Software

Vendor

• langflow-ai

Name

• langflow

Version

• 1.9.0
• 1.9.1

Website

• Product: https://github.com/langflow-ai/langflow/

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