Description
Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.0.19, an attacker can send a /api/v1/files/upload/ request without any authentication token/cookies and abuse a very long multipart form boundary to make the langflow app unusable for all users for an indefinite amount of time. This vulnerability is fixed in 1.0.19.
Published: 2026-06-23
Score: 7.5 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

Langflow is a tool for building and deploying AI‑powered agents and workflows. Prior to 1.0.19, an attacker can send a /api/v1/files/upload/ request without any authentication token or cookie and abuse a very long multipart form boundary, a resource exhaustion weakness (CWE‑400), to make the langflow app unusable for all users for an indefinite amount of time. The vulnerability is fixed in 1.0.19.

Affected Systems

The flaw affects the Langflow application by langflow‑ai, specifically versions prior to 1.0.19. Users running v1.0.18 or earlier are vulnerable.

Risk and Exploitability

With a CVSS score of 7.5, the vulnerability is considered high severity. The EPSS score is not available and the issue is not listed in the CISA KEV catalog. The likely attack vector is any network client that can reach the Langflow service, which can send an unauthenticated /api/v1/files/upload/ request with a specially crafted multipart form boundary to exhaust server resources, resulting in a denial of service for all users.

Generated by OpenCVE AI on June 24, 2026 at 11:45 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Upgrade Langflow to version 1.0.19 or later, which contains the patch for the multipart form boundary issue.
  • If an immediate upgrade is not possible, restrict unauthenticated access to the /api/v1/files/upload/ endpoint using firewall rules or application‑level rate limiting.
  • Implement authentication or additional access controls before the upload endpoint to prevent unauthenticated usage.

Generated by OpenCVE AI on June 24, 2026 at 11:45 UTC.

Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-qwqc-p3q8-wcg9 Langflow: Unauthenticated DoS through multipart form boundary file upload
History

Wed, 24 Jun 2026 16:15:00 +0000

Type Values Removed Values Added
First Time appeared Langflow
Langflow langflow
Vendors & Products Langflow
Langflow langflow

Tue, 23 Jun 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Tue, 23 Jun 2026 16:45:00 +0000

Type Values Removed Values Added
Description Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.0.19, an attacker can send a /api/v1/files/upload/ request without any authentication token/cookies and abuse a very long multipart form boundary to make the langflow app unusable for all users for an indefinite amount of time. This vulnerability is fixed in 1.0.19.
Title Langflow: Unauthenticated DoS through multipart form boundary file upload
Weaknesses CWE-400
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Subscriptions

Langflow Langflow
cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-06-23T17:56:37.766Z

Reserved: 2026-06-16T21:59:57.018Z

Link: CVE-2026-55446

cve-icon Vulnrichment

Updated: 2026-06-23T17:56:26.114Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-24T16:00:06Z

Weaknesses
  • CWE-400

    Uncontrolled Resource Consumption