CVE-2026-21445 is a critical security vulnerability identified in the langflow AI tool, which is used for building and deploying AI-powered agents and workflows. The vulnerability stems from missing authentication controls on multiple critical API endpoints in langflow versions earlier than 1.7.0.dev45. These endpoints manage sensitive operations including access to user conversation data, transaction histories, and system-level functions such as message deletion. Due to the absence of authentication, any unauthenticated user can remotely invoke these endpoints without restriction, leading to unauthorized data disclosure and potential destructive actions. The vulnerability is classified under CWE-306 (Missing Authentication for Critical Function), highlighting the failure to enforce proper access controls on sensitive functions. The CVSS v4.0 score of 8.8 reflects the high impact on confidentiality and integrity, combined with the ease of exploitation (no privileges or user interaction required). The flaw was publicly disclosed on January 2, 2026, and has been addressed in langflow version 1.7.0.dev45. While no active exploits have been reported, the vulnerability’s characteristics make it a prime target for attackers seeking to compromise AI workflow environments. Organizations relying on langflow for AI automation and data processing must urgently apply the patch to mitigate risks associated with unauthorized data access and operational interference.

For European organizations, this vulnerability poses significant risks to the confidentiality and integrity of sensitive AI-driven workflows and user data. Unauthorized access to conversation data and transaction histories can lead to data breaches involving personal or proprietary information, potentially violating GDPR and other data protection regulations. The ability to perform destructive operations such as message deletion could disrupt business processes, degrade service availability, and undermine trust in AI systems. Organizations in sectors with high reliance on AI automation—such as finance, healthcare, and technology—may face operational disruptions and reputational damage. Furthermore, the lack of authentication means attackers can exploit the vulnerability remotely without prior access, increasing the attack surface. The potential regulatory penalties and operational costs associated with data breaches and service interruptions make this vulnerability particularly impactful for European entities.

The primary mitigation is to upgrade langflow installations to version 1.7.0.dev45 or later, which includes the necessary authentication controls on all critical API endpoints. Organizations should audit their current langflow deployments to identify affected versions and prioritize patching. In addition to patching, implement network-level protections such as restricting access to langflow API endpoints via firewalls or VPNs to trusted users and systems only. Employ API gateway solutions that enforce authentication and authorization policies as an additional security layer. Conduct regular security assessments and penetration tests focused on AI workflow tools to detect similar misconfigurations. Maintain strict monitoring and logging of API access to detect and respond to unauthorized attempts promptly. Finally, ensure that sensitive data handled by langflow is encrypted both in transit and at rest to minimize exposure in case of compromise.