Auth bypass in Langflow
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 belo…
Vulnerability class: IDOR (Insecure Direct Object Reference)
EPSS: 0.291 (98.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.4 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:L.
Affected products
- Langflow
- Langflow-ai Langflow — versions < 1.9.2, < 1.9.1
Weakness classification (CWE)
CISA KEV (Known Exploited Vulnerabilities)
This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.
BOD 22-01 due date: .
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.
Public proof-of-concept exploits
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Mitigation, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC, Issue Tracking)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Third Party Advisory)
- 134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)
- security-advisories@github.com (Patch, x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-55255?
- CVE-2026-55255 is a high-severity vulnerability in Langflow, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 8.4/10. Published 2026-06-23.
- How severe is CVE-2026-55255?
- High severity. CVSS v3 base score is 8.4 out of 10.
- Is CVE-2026-55255 known to be exploited?
- Yes. CVE-2026-55255 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2026-07-07), indicating it is being actively exploited. 1 public proof-of-concept repositories are indexed.