CVE-2026-55255Langflow: IDOR Vulnerability in `/api/v1/responses` Endpoint Allows Authenticated Attackers to Access Another User's Flow
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.
Overview
Severity
| Score | Severity | Version | Vector String |
|---|---|---|---|
| 8.4 | HIGH | 3.1GitHub_M (CNA) | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L |
CISA required action
⚡ Known exploited · remediation due Jul 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 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.
Details
- CVE ID
- CVE-2026-55255
- Status
- Analyzed
- Assigner (CNA)
- GitHub_M
- Published
- Jun 23, 2026
- Last modified
- 2026-10-25 23:10 UTC
- Weaknesses
- CWE-639 · Authorization Bypass Through User-Controlled Key
Affected Products
As published by the CNA in the CVE record.
langflow-ailangflow1 version range
- < 1.9.1
References
- github.com https://github.com/langflow-ai/langflow/commit/2c9f498d664a3c32698b57d7c5e752625291060e
- github.com https://github.com/langflow-ai/langflow/pull/12832
- github.com https://github.com/langflow-ai/langflow/security/advisories/GHSA-qrpv-q767-xqq2
- webflow.sysdig.com https://webflow.sysdig.com/blog/understanding-langflow-cve-2026-55255-and-why-higher-cvss-vulnerabilities-arent-always-the-most-exploited
- cisa.gov https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-55255