CVE-2026-55450

Langflow: Unauthenticated file upload leads to DoS (space exhaustion) and information leak

Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.1, unauthenticated users can upload any amount of data to the server without any limitations. No need for any prior knowledge, only network access to Langflow. This can lead to space exhaustion on the server. In addition, in the response, the absolute path of the uploaded file is reported to the attacker, which is an information leak that can assist in chaining other primitives. This vulnerability is fixed in 1.9.1.

Affected

langflow-ai · langflow

CVSS v3.1 GITHUB

9.3 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:H

EPSS

1.19% chance of exploitation in the next 30 days, 67th percentile

Nuclei

critical

Published

2026-06-23

Proof-of-concept exploits (3)

• advisories/GHSA-x223-p2gf-v735
• samael0x4/CVE-20261★ · 2026-08-01
• 0xBlackash/CVE-2026-554500★ · 2026-10-08

Nuclei templates (1)

• projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-55450.yaml

Security advisories

• langflow-ai/langflow/security/advisories/GHSA-x223-p2gf-v735
• langflow-ai/langflow/pull/12831

References

• CVE Record
• NVD entry

Related

• CVE-2026-0770
• CVE-2026-21643
• CVE-2026-21962