CVE-2026-55446

Langflow: Unauthenticated DoS through multipart form boundary file upload

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.

Affected

langflow-ai · langflow

CVSS v3.1 GITHUB

7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

0.58% chance of exploitation in the next 30 days, 47th percentile

Published

2026-06-23

Proof-of-concept exploits (1)

• advisories/GHSA-qwqc-p3q8-wcg9

Security advisories

• langflow-ai/langflow/security/advisories/GHSA-qwqc-p3q8-wcg9
• langflow-ai/langflow/pull/3923

References

• CVE Record
• NVD entry