CVE-2026-9225 in Langflow OSS
Summary
by MITRE • 09/10/2026
IBM Langflow OSS 1.0.0 through 1.11.5 Langflow could allow an authenticated attacker to access sensitive files belonging to other users due to improper access control in the File/Read File component. When executing flows through the /api/v1/run/advanced/{flow_id} endpoint, the application allows component inputs to reference storage paths using arbitrary user or flow identifiers without verifying ownership. An attacker with low‑privileged authenticated access can supply a crafted file path pointing to another user’s storage namespace, causing the backend to read and return the contents of files uploaded by other users. This vulnerability bypasses intended authorization checks enforced by the file management API and may result in unauthorized disclosure of sensitive user data.
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Analysis
by VulDB Data Team • 09/10/2026
The vulnerability identified within IBM Langflow versions 1.0.0 through 1.11.5 represents a critical failure in server-side access control mechanisms, specifically affecting the File/Read File component. This flaw allows an authenticated attacker with low-privileged access to bypass intended authorization checks and retrieve sensitive files belonging to other users. The root cause lies in how the application handles file path references during flow execution via the /api/v1/run/advanced/{flow_id} endpoint. Instead of validating that the requesting user owns the resource being accessed, the system permits component inputs to reference storage paths using arbitrary user or flow identifiers without verifying ownership. This lack of strict identity verification creates a direct pathway for unauthorized data disclosure, undermining the fundamental security principle of least privilege and multi-tenant isolation within the application environment.
From a technical perspective, this vulnerability is classified as an Insecure Direct Object Reference (IDOR), which corresponds to CWE-639 in the Common Weakness Enumeration standard. The attacker exploits the flexibility of the flow execution engine by crafting specific file paths that point outside their designated storage namespace. By manipulating these identifiers, the backend processes the request and returns the contents of files uploaded by other users, effectively bypassing the access control logic enforced by the underlying file management API. This behavior indicates a failure in server-side validation where trust is incorrectly placed on client-supplied input regarding resource ownership. The vulnerability aligns with ATT&CK technique T1078, Valid Accounts, as it requires initial authentication but leverages those credentials to perform unauthorized actions that exceed their intended permissions scope.
The operational impact of this flaw is severe, particularly in environments where Langflow is deployed for collaborative data science or machine learning workflows involving multiple tenants or users with varying levels of access. The ability to read arbitrary files can lead to the exfiltration of personally identifiable information (PII), proprietary algorithms, sensitive configuration details, or other confidential business intelligence stored within the user's workspace. This unauthorized disclosure not only violates privacy regulations such as GDPR or HIPAA but also erodes trust in the platform’s security posture. Attackers could potentially chain this vulnerability with others to escalate privileges further or use the stolen data for social engineering attacks against targeted individuals or organizations.
To mitigate this risk, immediate remediation should focus on implementing robust server-side access control checks within the File/Read File component and the broader file management API. Developers must ensure that every request to read a file is validated against an authoritative source of truth regarding user ownership before any I/O operations are performed. This includes verifying that the authenticated session’s identity matches the owner identifier embedded in or referenced by the requested resource path. Additionally, implementing strict input validation and sanitization for all component inputs can help prevent manipulation of storage paths. Regular security audits and penetration testing focused on access control logic are recommended to identify similar flaws across other endpoints. Until a patch is applied, restricting network exposure of the Langflow instance and enforcing strong authentication policies with multi-factor authentication can reduce the attack surface available to potential adversaries.