CVE-2026-55450

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

Published Jun 23, 2026 CVSS 3.1 · 9.3 Critical EPSS 1.2% KEV · Not listed

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.

Analysis

Technical impact

The vulnerability arises from an unauthenticated file upload endpoint that accepts files of unlimited size, requiring only network access and no prior credentials. An attacker can flood the server’s storage, exhausting space and causing a denial of service. The response also leaks the absolute path of the uploaded file, exposing sensitive filesystem information that could be leveraged in further attacks. Authentication (CWE‑306), Uncontrolled Resource Consumption (CWE‑400), and Information Exposure (CWE‑200).

Affected Systems

Langflow (langflow-ai:langflow) older than version 1.9.1. Any deployment of Langflow 1.8 unauthenticated users over the network is vulnerable.

Risk and Exploitability

The score of 9.3 marks this vulnerability as critical. Because no authentication is required and there are no size limits, the attack will succeed from any host able to reach the Langflow instance. The EPSS score is 1%, indicating a low probability of widespread exploitation, yet the clear attack surface still poses a focused risk. The vulnerability has not appeared in the CISA KEV catalog yet, but its severity warrants urgent remediation. The likely attack vector is remote network access to the upload endpoint.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

langflow-ai

langflow

affected

Version	Status	Constraints
`< 1.9.1`	affected	—

Configuration 1 [-]

cpe:2.3:a:langflow:langflow:*:*:*:*:*:*:*:*

No data.

Vendor Product Versions

Langflow

Version	Status	Scheme	Platform
`[0,1.9.1)`	affected	semver	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Upgrade Langflow to version 1.9.1 or later to fix the upload controls and suppress path exposure.
If an upgrade is not possible, enforce authentication on the upload endpoint to restrict access only authorized users.
Implement file size limits or storage quotas on the upload folder to mitigate space exhaustion.
Sanitize or remove absolute file paths from server responses to avoid leaking filesystem details.

Generated by OpenCVE AI on August 24, 2026 at 22:24 UTC.

Tracking

Advisories

Source	ID	Title
Github GHSA	GHSA-x223-p2gf-v735	Langflow: Unauthenticated file upload leads to DoS (space exhaustion) and information leak

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Changed

Confidentiality Impact Low

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: 1.2% (1.190% probability within 30 days)

Exploitation poc

Automatable yes

Technical Impact partial

References

Link	Providers
https://github.com/langflow-ai/langflow/pull/12831
https://github.com/langflow-ai/langflow/security/advisories/GHSA-x223-p2gf-v735

History

Jun 24, 2026 4:15 PM First appearance in the feed. Affected vendors updated View changes

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

Jun 23, 2026 5:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Jun 23, 2026 4:45 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
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.
Title		Langflow: Unauthenticated file upload leads to DoS (space exhaustion) and information leak
Weaknesses		CWE-200 CWE-306 CWE-400
References		https://github.com/langflow-ai/langflow/pull/12831 https://github.com/langflow-ai/langflow/security/advisories/GHSA-x223-p2gf-v735
Metrics		cvssV3_1 `{'score': 9.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:H'}`