CVE-2026-9103 in Langflow OSS
Summary
by MITRE • 07/17/2026
IBM Langflow OSS 1.0.0 through 1.10.0 could allow a remote attacker to gain unauthorized access due to improper authentication in the /api/v1/login/auto_login endpoint. The endpoint issues long-lived superuser bearer tokens without requiring authentication when the AUTO_LOGIN configuration is enabled (enabled by default), which may allow an unauthenticated network attacker to obtain full administrative access. Additionally, permissive cross-origin resource sharing (CORS) settings may allow tokens to be exposed to unintended origins, increasing the risk of unauthorized access.
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Analysis
by VulDB Data Team • 07/17/2026
This vulnerability exists within IBM Langflow Open Source Software versions 1.0.0 through 1.10.0 where the /api/v1/login/auto_login endpoint fails to properly validate authentication requests. The flaw stems from the automatic login functionality that operates when the AUTO_LOGIN configuration parameter is enabled, which happens to be set as default in these releases. When this configuration is active, the system generates long-lived superuser bearer tokens without requiring any form of authentication validation, creating a critical security gap that allows remote attackers to bypass normal access controls entirely.
The technical implementation of this vulnerability aligns with CWE-287 which addresses improper authentication issues in software systems. The flaw represents an authentication bypass where the system assumes trust in certain conditions rather than enforcing proper credential verification processes. Attackers can exploit this by simply accessing the auto_login endpoint without providing any valid credentials, thereby obtaining administrative tokens that grant full control over the system's functionality and data. This creates a scenario where unauthorized network actors can achieve complete system compromise without needing to perform complex exploitation techniques.
The operational impact of this vulnerability is severe as it provides attackers with immediate administrative access to the entire Langflow instance. With superuser privileges, an attacker can modify or delete all system configurations, access sensitive data, manipulate workflows, and potentially use the compromised system as a pivot point for further attacks within the network. The long-lived nature of these tokens means that once obtained, they remain valid for extended periods, allowing attackers to maintain persistent access without needing to re-exploit the vulnerability. Additionally, the permissive CORS configuration exacerbates this risk by potentially exposing authentication tokens to unintended origins, making it easier for attackers to harvest tokens through cross-site scripting or similar techniques.
The default enablement of AUTO_LOGIN functionality compounds the severity of this issue significantly. Systems administrators may unknowingly deploy vulnerable configurations without realizing that administrative access is automatically granted to anyone who can reach the endpoint. This configuration management flaw represents a dangerous default setting that prioritizes convenience over security, making the vulnerability more likely to be exploited in production environments. The combination of weak authentication and permissive CORS settings creates multiple attack vectors that increase the probability of successful exploitation while simultaneously reducing the effort required by attackers to achieve full system compromise.
Organizations should immediately disable the AUTO_LOGIN feature through configuration changes or implement strict access controls to prevent unauthorized access to the auto_login endpoint. Network segmentation and firewall rules should be implemented to restrict access to this specific API endpoint to only trusted internal systems. Additionally, administrators must review and tighten CORS policies to ensure that authentication tokens are not exposed to untrusted origins. The recommended mitigation strategy involves implementing proper authentication mechanisms for all endpoints, including the auto_login endpoint, and ensuring that token generation requires valid credential validation before issuing administrative privileges. This vulnerability demonstrates the critical importance of secure default configurations and proper authentication implementation in open source software deployments.
This vulnerability classification aligns with ATT&CK technique T1078 which covers legitimate credentials usage, specifically focusing on the exploitation of default credentials or automated login mechanisms that bypass normal authentication controls. The security implications extend beyond simple credential theft to include full system compromise and potential lateral movement within network environments where such systems may be deployed. Organizations utilizing IBM Langflow should conduct immediate security assessments of their deployments and implement the necessary configuration changes to address this authentication bypass vulnerability.