Vulnerability Intelligence Report
Langflow: IDOR Vulnerability in `/api/v1/responses` Endpoint Allows Authenticated Attackers to Access Another User's Flow
CVE-2026-55255
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.
CISA KEV
SSVC: Active Exploitation
CVSS Base Score
8.4
HIGH
Exploitability:1.8
Impact Score:6.0
EPSS Probability:0.47%
Executive Threat Verdict
Evaluating...
Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
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Authentication
—
Weaponization
—
SSVC Action
—
Weaknesses (CWE)
CWE-639 ↗CWE-639: Authorization Bypass Through User-Controlled Key
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| langflow-ai | langflow | < 1.9.1 (affected) |
References & Technical Advisories
No reference links found.
Threat Intelligence Signals
Identity & Timeline
| Status | PUBLISHED |
| Assigning Authority | GitHub, Inc. · Vendor · USA |
| Reserved | 2026-06-16T16:44:00 |
| Published | 2026-06-23T16:28:20 |
| Last Updated | 2026-07-08T03:56:30 |
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