CVE-2026-81211 in Langflow OSS
Summary
by MITRE • 09/10/2026
IBM Langflow OSS 1.0.0 through 1.11.5 could allow a remote authenticated attacker to execute arbitrary Python code due to improper authorization of custom components in stored flows.
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Analysis
by VulDB Data Team • 09/10/2026
The vulnerability identified in IBM Langflow versions 1.0.0 through 1.11.5 represents a critical security flaw rooted in the application's handling of user-defined content within its workflow orchestration engine. Langflow is designed to facilitate the creation and management of large language model applications by allowing users to construct complex flows using various components, including custom Python code snippets. The core issue lies in the improper authorization mechanisms governing these stored flows, specifically when they involve custom components that execute arbitrary logic. This architectural weakness permits a remote authenticated attacker who has access to create or modify flows within the system to inject malicious Python payloads into the execution environment of other users' workflows or even their own privileged contexts if permission boundaries are insufficiently enforced.
From a technical perspective, this vulnerability is classified under CWE-94 as Improper Control of Generation of Code (Code Injection). The flaw exploits the trust relationship between the application framework and the user-provided code modules. When a flow containing custom components is loaded or executed, the system fails to adequately validate whether the executing context has the necessary permissions for that specific action or component type. This lack of granular access control allows an attacker to bypass intended security boundaries by crafting flows that trigger unintended side effects during runtime. The attacker leverages this misconfiguration to achieve arbitrary code execution on the server hosting the Langflow instance, effectively gaining a foothold within the backend infrastructure.
The operational impact of this vulnerability is severe and far-reaching. Successful exploitation allows an authenticated user to execute arbitrary Python commands with the privileges of the application process. This can lead to full system compromise, including data exfiltration, modification or destruction of stored flows and associated datasets, installation of backdoors for persistent access, and lateral movement within the internal network if the Langflow server has connectivity to other critical systems. Since authentication is required, this vulnerability primarily affects environments where multiple users have accounts but lack strict segregation of duties or role-based access controls that would prevent lower-privileged users from influencing higher-privilege execution contexts.
In terms of threat modeling and industry standards, this scenario aligns with MITRE ATT&CK technique T1059 Command and Scripting Interpreter, specifically the Python sub-category (T1059.006). The attacker utilizes legitimate system utilities or interpreters to perform malicious actions, blending in with normal operational traffic until deeper inspection reveals anomalous behavior. Furthermore, this falls under CWE-284 Improper Access Control, highlighting a failure in enforcing least privilege principles during the execution of user-supplied logic.
To mitigate this risk, organizations running affected versions must immediately upgrade IBM Langflow to version 1.11.6 or later, where these authorization checks have been hardened. In addition to patching, administrators should implement strict role-based access controls (RBAC) that limit which users can create flows containing custom code components. It is also advisable to isolate the Langflow execution environment using containerization with restricted capabilities and network policies to minimize the blast radius in case of a successful exploit. Regular auditing of stored flows for suspicious patterns or unauthorized modifications should be integrated into operational security practices, alongside monitoring system logs for unusual process executions originating from the application service account.