CVE-2026-19299: Langflow Path Traversal Vulnerability

CVE-2026-19299 Overview

CVE-2026-19299 is a path traversal vulnerability [CWE-22] affecting IBM Langflow OSS versions 1.0.0 through 1.11.2. A remote authenticated attacker can exploit the flaw to read sensitive files outside the intended directory scope. The issue is network-accessible, requires low privileges, and does not require user interaction. Successful exploitation results in disclosure of confidential information stored on the host running Langflow.

Critical Impact
Authenticated attackers can traverse the file system to read arbitrary files accessible to the Langflow process, exposing configuration data, credentials, and application secrets.

Affected Products

IBM Langflow OSS versions 1.0.0 through 1.11.2
Deployments on Linux, Apple macOS, and Microsoft Windows hosts
Any Langflow instance exposed to authenticated users on the network

Discovery Timeline

2026-09-04 - CVE-2026-19299 published to NVD
2026-09-08 - Last updated in NVD database

Technical Details for CVE-2026-19299

Vulnerability Analysis

The flaw resides in file-handling logic within Langflow OSS that fails to sanitize user-supplied path input. An authenticated attacker submits crafted path parameters containing traversal sequences such as ../ to escape the intended base directory. The Langflow process then reads files outside the sanctioned scope and returns their contents in the response. Impact is limited to confidentiality; the vulnerability does not directly permit modification of files or disruption of service, per the CVSS vector.

Root Cause

The root cause is improper limitation of a pathname to a restricted directory [CWE-22]. Langflow accepts user-controlled path components and passes them to file-read routines without canonicalizing the resulting path or verifying it remains within the allowed base directory. Attackers combine relative traversal segments with valid path prefixes to bypass any weak filtering that may be in place.

Attack Vector

Exploitation requires network reachability to the Langflow HTTP interface and valid authentication at any privilege level. The attacker issues requests to an endpoint that consumes a filename or path argument and substitutes traversal sequences to reference targets such as /etc/passwd, application configuration files, or files containing API keys and model credentials. No user interaction is required. See the IBM Support Article for advisory details.

No public proof-of-concept exploit is available at the time of publication. Refer to the vendor advisory for technical specifics.

Detection Methods for CVE-2026-19299

Indicators of Compromise

HTTP requests to Langflow endpoints containing traversal sequences such as ../, ..\, or URL-encoded variants %2e%2e%2f and %2e%2e%5c.
Access log entries showing unusual filename parameters referencing paths outside the Langflow working directory.
Langflow process activity reading sensitive system files such as /etc/passwd, .env, or SSH key files.

Detection Strategies

Inspect web application firewall and reverse proxy logs for path traversal patterns targeting Langflow API routes.
Correlate authenticated Langflow session activity with unexpected file-read operations on the host.
Alert on responses from Langflow endpoints whose payloads contain content signatures typical of OS configuration files.

Monitoring Recommendations

Enable verbose request logging on the Langflow service and forward logs to a centralized analytics platform.
Monitor file-system access by the Langflow process user for reads outside the application data directory.
Track authentication events for Langflow accounts and flag session activity that deviates from normal usage.

How to Mitigate CVE-2026-19299

Immediate Actions Required

Upgrade IBM Langflow OSS to a fixed release above 1.11.2 as directed by the IBM Support Article.
Restrict network access to Langflow instances to trusted users and networks only.
Rotate credentials, API keys, and secrets that may have been readable by the Langflow process account.

Patch Information

IBM has published remediation guidance for CVE-2026-19299 in the IBM Support Article. Administrators should review the advisory to identify the fixed version applicable to their deployment and plan an upgrade window.

Workarounds

Place Langflow behind a reverse proxy or WAF that blocks requests containing path traversal sequences and encoded equivalents.
Run the Langflow process under a dedicated low-privilege account with file-system permissions scoped to the application directory only.
Disable or restrict Langflow endpoints that accept filename or path parameters if they are not required in your deployment.

bash

# Example nginx rule to reject traversal patterns in Langflow requests
location /api/ {
    if ($request_uri ~* "(\.\./|\.\.\\|%2e%2e%2f|%2e%2e%5c)") {
        return 403;
    }
    proxy_pass http://langflow_backend;
}