CVE-2026-55450

CRITICAL NUCLEI

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

Title source: cna
STIX 2.1

Exploitation Summary

CVE-2026-55450 has a Nuclei detection template available — see the Nuclei card below for the Shodan/FOFA recon queries.

Description

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.

Nuclei Templates (1)

Langflow < 1.9.1 - Unauthenticated File Upload
CRITICALVERIFIEDby xtr0nix

References (2)

Core 2
Core References
X_Refsource_Misc x_refsource_misc
https://github.com/langflow-ai/langflow/pull/12831

Scores

CVSS v3 9.3
EPSS 0.0640
EPSS Percentile 93.0%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact partial

Details

CWE
CWE-200 CWE-306 CWE-400
Status published
Products (2)
langflow/langflow < 1.9.1
langflow-ai/langflow < 1.9.1
Published Jun 23, 2026
Tracked Since Jun 23, 2026