CVE-2026-55450 PoC — Langflow: Unauthenticated file upload leads to DoS (space exhaustion) and information leak

Source

https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-55450.yaml

Associated Vulnerability

Title: Langflow: Unauthenticated file upload leads to DoS (space exhaustion) and information leak (CVE-2026-55450)
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.

Description

Langflow < 1.9.1 contains an unrestricted file upload caused by lack of upload limitations, letting unauthenticated attackers exhaust server space and leak absolute file paths, exploit requires network access.

File Snapshot

Remarks

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