Langflow’s AI Dev Platform Exposed: Uncovering the Path Traversal Vulnerability

Exploitation of High-Severity Vulnerability in Langflow AI Development Platform

Recent reports have revealed that attackers are actively taking advantage of CVE-2026-5027, a critical path traversal vulnerability present in the popular AI development platform known as Langflow. This vulnerability allows malicious actors to write arbitrary files on servers that are exposed to the internet.

Langflow, a widely-used open-source visual platform for creating AI applications, AI agents, Retrieval-Augmented Generation (RAG) systems, and MCP-based workflows, offers a unique drag-and-drop interface for development, making it a favorite among AI development teams. With over 149,000 stars and 9,200 forks on GitHub, Langflow has established itself as a prominent player in the AI development space.

The vulnerability (CVE-2026-5027) in Langflow stems from a flaw in its file upload functionality, specifically in how it handles user-supplied filenames. Tenable, the cybersecurity firm that discovered the issue, noted that the ‘POST /api/v2/files’ endpoint fails to properly sanitize the ‘filename’ parameter from the multipart form data, enabling attackers to write files to any location on the filesystem using path traversal sequences like ‘../’.

Despite Tenable’s efforts to responsibly disclose the vulnerability, Langflow did not respond promptly. Tenable publicly disclosed the issue on March 27, 2026. Subsequently, Snyk Security confirmed that the vulnerability was patched in langflow-base package version 0.8.3 and Langflow application version 1.9.0.

Security researcher Caitlin Condon reported that attackers have already begun exploiting CVE-2026-5027 by dropping test files on vulnerable instances of Langflow. Due to Langflow’s default unauthenticated auto-login feature, attackers can easily access the vulnerable endpoint without requiring any credentials, further facilitating the exploitation process.

Censys scans have identified approximately 7,000 publicly exposed Langflow instances, indicating a significant risk posed by this vulnerability. However, it is essential to note that historical scan results may not accurately reflect current exposure levels.

Following the recent exploitation of CVE-2026-5027, Langflow users are strongly advised to upgrade to the latest release, version 1.10.0, to mitigate the risk of potential attacks.

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