CVE-2026-19299 in Langflow OSS
Summary
by MITRE • 09/04/2026
IBM Langflow OSS 1.0.0 through 1.11.2 could allow a remote authenticated attacker to obtain sensitive information due to path traversal.
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Analysis
by VulDB Data Team • 09/04/2026
The vulnerability identified in IBM Langflow versions 1.0.0 through 1.11.2 represents a critical security flaw rooted in improper input validation and insufficient sanitization of user-supplied file paths. This specific weakness is classified under the Common Weakness Enumeration as CWE-22, which defines Improper Limitation of a Pathname to a Restricted Directory, commonly known as path traversal or directory traversal. The core technical issue arises when the application processes requests intended for static asset retrieval or file serving without adequately normalizing or validating the input parameters. An attacker can exploit this by constructing malicious HTTP requests that contain sequences designed to escape the designated web root or data directory, such as using dot-dot-slash characters followed by absolute path indicators. Because Langflow is an open-source platform often deployed in development and production environments for building large language model applications, it frequently handles sensitive configuration files, source code artifacts, or internal application resources that are not intended to be publicly accessible via the web interface.
From a technical perspective, the flaw allows a remote authenticated attacker to bypass access controls by manipulating file path arguments within API endpoints or static file handlers. Authentication is required because Langflow typically restricts certain administrative functions and resource accesses to verified users, but this authentication layer does not mitigate the underlying logic error in how paths are resolved on the server side. When the application receives a request with a crafted filename parameter containing traversal sequences, it fails to strip these malicious components before passing them to the operating system's file I/O routines. Consequently, instead of serving a legitimate asset from within the allowed directory structure, the server reads and returns content from arbitrary locations in the filesystem where the service account has read permissions. This behavior effectively turns the application into an unauthorized information disclosure mechanism, allowing attackers to probe the underlying infrastructure for sensitive data such as environment variables, database credentials stored in configuration files, or proprietary source code contained within project directories.
The operational impact of this vulnerability is significant, particularly given Langflow's role in facilitating AI and machine learning workflows that often involve processing sensitive intellectual property and personal data. Successful exploitation enables an authenticated user to exfiltrate confidential information that could compromise the entire deployment environment. The leaked data may include API keys for third-party services, internal network topology details inferred from file structures, or proprietary algorithms central to business operations. Furthermore, in multi-tenant deployments where multiple users share a single instance of Langflow, this vulnerability allows one authenticated user to access resources belonging to other tenants or the system administrator, leading to a severe breach of confidentiality and potential violation of data protection regulations such as GDPR or HIPAA depending on the nature of the processed data. The ability to read arbitrary files also serves as a reconnaissance step that could facilitate further attacks, including remote code execution if combined with other vulnerabilities like deserialization flaws or insecure file uploads.
To mitigate this risk, immediate action is required for all organizations running affected versions of IBM Langflow. The primary remediation strategy is to upgrade the software to version 1.12.0 or later, where the developers have implemented stricter input validation and path normalization mechanisms to prevent directory traversal attacks. For environments that cannot be immediately upgraded due to dependency constraints, temporary mitigations should include restricting network access to the Langflow interface by placing it behind a reverse proxy with strict URL filtering capabilities capable of blocking common traversal patterns such as dot-dot-slash sequences. Additionally, administrators should enforce principle of least privilege for the user account running the Langflow process, ensuring that even if an attacker succeeds in reading files, they are limited to accessing only those resources strictly necessary for application operation and not sensitive system-wide configurations or credentials. Regular security audits and static code analysis tools focused on CWE-22 patterns can also help identify similar vulnerabilities in custom integrations built upon the Langflow framework.