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9.9
CRITICAL CVSS 3.1
CVE-2026-33309
Langflow has an Arbitrary File Write (RCE) via v2 API
Overview
Description

Langflow is a tool for building and deploying AI-powered agents and workflows. Versions 1.2.0 through 1.8.1 have a bypass of the patch for CVE-2025-68478 (External Control of File Name), leading to the root architectural issue within `LocalStorageService` remaining unresolved. Because the underlying storage layer lacks boundary containment checks, the system relies entirely on the HTTP-layer `ValidatedFileName` dependency. This defense-in-depth failure leaves the `POST /api/v2/files/` endpoint vulnerable to Arbitrary File Write. The multipart upload filename bypasses the path-parameter guard, allowing authenticated attackers to write files anywhere on the host system, leading to Remote Code Execution (RCE). Version 1.9.0 contains an updated fix.

Details
INFO

Published Date :

March 24, 2026, 1:16 p.m.

Last Modified :

March 24, 2026, 1:16 p.m.

Remotely Exploit :

Yes !

Source :

[email protected]
Impact
Affected Products

The following products are affected by CVE-2026-33309 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Langflow langflow
: Total Affected Vendor : 1 | Products : 1
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 CRITICAL [email protected]
Solution
Update Langflow to version 1.9.0 or later to address arbitrary file write vulnerabilities.
  • Update Langflow to version 1.9.0 or later.
  • Verify that file upload protections are properly configured.
References
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-33309.

URL Resource
https://github.com/langflow-ai/langflow/security/advisories/GHSA-g2j9-7rj2-gm6c
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-33309 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-33309 weaknesses.

CAPEC-64: Using Slashes and URL Encoding Combined to Bypass Validation Logic Using Slashes and URL Encoding Combined to Bypass Validation Logic CAPEC-76: Manipulating Web Input to File System Calls Manipulating Web Input to File System Calls CAPEC-78: Using Escaped Slashes in Alternate Encoding Using Escaped Slashes in Alternate Encoding CAPEC-79: Using Slashes in Alternate Encoding Using Slashes in Alternate Encoding CAPEC-126: Path Traversal Path Traversal CAPEC-13: Subverting Environment Variable Values Subverting Environment Variable Values CAPEC-64: Using Slashes and URL Encoding Combined to Bypass Validation Logic Using Slashes and URL Encoding Combined to Bypass Validation Logic CAPEC-72: URL Encoding URL Encoding CAPEC-76: Manipulating Web Input to File System Calls Manipulating Web Input to File System Calls CAPEC-78: Using Escaped Slashes in Alternate Encoding Using Escaped Slashes in Alternate Encoding CAPEC-79: Using Slashes in Alternate Encoding Using Slashes in Alternate Encoding CAPEC-80: Using UTF-8 Encoding to Bypass Validation Logic Using UTF-8 Encoding to Bypass Validation Logic CAPEC-267: Leverage Alternate Encoding Leverage Alternate Encoding CAPEC-35: Leverage Executable Code in Non-Executable Files Leverage Executable Code in Non-Executable Files CAPEC-77: Manipulating User-Controlled Variables Manipulating User-Controlled Variables CAPEC-242: Code Injection Code Injection CAPEC-19: Embedding Scripts within Scripts Embedding Scripts within Scripts CAPEC-441: Malicious Logic Insertion Malicious Logic Insertion CAPEC-478: Modification of Windows Service Configuration Modification of Windows Service Configuration CAPEC-479: Malicious Root Certificate Malicious Root Certificate CAPEC-502: Intent Spoof Intent Spoof CAPEC-503: WebView Exposure WebView Exposure CAPEC-536: Data Injected During Configuration Data Injected During Configuration CAPEC-546: Incomplete Data Deletion in a Multi-Tenant Environment Incomplete Data Deletion in a Multi-Tenant Environment CAPEC-550: Install New Service Install New Service CAPEC-551: Modify Existing Service Modify Existing Service CAPEC-552: Install Rootkit Install Rootkit CAPEC-556: Replace File Extension Handlers Replace File Extension Handlers CAPEC-558: Replace Trusted Executable Replace Trusted Executable CAPEC-562: Modify Shared File Modify Shared File CAPEC-563: Add Malicious File to Shared Webroot Add Malicious File to Shared Webroot CAPEC-564: Run Software at Logon Run Software at Logon CAPEC-578: Disable Security Software Disable Security Software

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-33309 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-33309 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Mar. 24, 2026

    Action Type Old Value New Value
    Added Description Langflow is a tool for building and deploying AI-powered agents and workflows. Versions 1.2.0 through 1.8.1 have a bypass of the patch for CVE-2025-68478 (External Control of File Name), leading to the root architectural issue within `LocalStorageService` remaining unresolved. Because the underlying storage layer lacks boundary containment checks, the system relies entirely on the HTTP-layer `ValidatedFileName` dependency. This defense-in-depth failure leaves the `POST /api/v2/files/` endpoint vulnerable to Arbitrary File Write. The multipart upload filename bypasses the path-parameter guard, allowing authenticated attackers to write files anywhere on the host system, leading to Remote Code Execution (RCE). Version 1.9.0 contains an updated fix.
    Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
    Added CWE CWE-22
    Added CWE CWE-94
    Added CWE CWE-284
    Added CWE CWE-73
    Added Reference https://github.com/langflow-ai/langflow/security/advisories/GHSA-g2j9-7rj2-gm6c
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
Base CVSS Score: 9.9
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact