CVE-2026-55255

High8.4Published on June 23, 2026

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.

Actively exploited

In the CISA exploited-vulnerabilities catalogue since Jul 7, 2026
US federal agencies must remediate it by Jul 10, 2026 (BOD 22-01)
First attack observed 2 days after disclosure

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 BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Source: CISA KEV · Aug 28, 2026 Aug 27, 2026 Aug 20, 2026 Aug 7, 2026 Jul 29, 2026 Jul 7, 2026

CVSS score8.4 / 10CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L

Weakness type (CWE)CWE-639

Vendorslangflow