Actively exploited in the wild
Langflow Authorization Bypass Through User-Controlled Key Vulnerability
Langflow - Langflow · Listed in the CISA KEV since 2026-07-07. This indicates confirmed attacks in production environments.
Required action: 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.
CVE-2026-55255
HighCVSS 8.4KEVExploitation Probability (EPSS)
Low risk35th percentile - higher than 35% of all known CVEs
Summary
In Langflow prior to 1.9.1, an IDOR vulnerability in the /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.
Risk Assessment
The organization is at risk of unauthorized execution of other users' AI flows, potentially leading to data leakage or process integrity compromise.
Recommendation
Immediately upgrade Langflow to version 1.9.1 or later, which includes a fix for this vulnerability.
Original NVD description (English source)
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.