Langflow: code injection in /api/v1/validate/code endpoint of Langflow AI (CVE-2025-3248) #shorts

Summary

Welcome to the Cyber Insights Podcast. Today we’re unpacking CVE-2025-3248, a critical remote code execution flaw in Langflow AI’s web service. Discovered in early April, this vulnerability allows an unauthenticated attacker to execute arbitrary code by targeting the /api/v1/validate/code endpoint. We’ll break down the impact, how it works, and what you need to do to stay safe.

Product details

Langflow AI is an open‑source flow‑based interface for building and validating AI prompts and workflows in Python. Versions up to and including 1.2.0 are affected. The vulnerable endpoint, /api/v1/validate/code, is designed to accept user‑supplied code for validation. It’s intended to check syntax and safety before execution, but it lacks proper authentication and validation controls.

Vulnerability type summary

This issue is classified under CWE-306: Missing Authentication for Critical Function. In practical terms, it’s a code injection flaw combined with no authorization checks. Attackers can send specially crafted HTTP requests to the validation endpoint, bypassing any login or permission checks and triggering arbitrary code execution on the server.

Details of the vulnerability

CVE-2025-3248 resides in how Langflow handles user‑provided code in the validation API. Without any authentication barrier, an attacker can inject Python payloads that the service will validate and execute. Proof‑of‑concept exploits surfaced immediately, and reports indicate active exploitation just two weeks after Langflow 1.3.0 was released. Successful attacks can lead to full server takeover, data theft, or pivoting deeper into the network.

Conclusion

If you’re running Langflow AI in any production or development environment, update to version 1.3.0 or later immediately. Block direct internet access to the validation endpoint, enforce strong authentication, and review your logs for suspicious requests. Stay vigilant—patch early, monitor continuously, and limit exposure of critical functions to prevent similar zero‑day style exploits in the future.

This chain involves the following actors

This following systems are involved

Attack entry point

Remediation actions

Exploitation actions

• https://github.com/langflow-ai/langflow/pull/6911
• https://github.com/langflow-ai/langflow/releases/tag/1.3.0
• https://www.horizon3.ai/attack-research/disclosures/unsafe-at-any-speed-abusing-python-exec-for-unauth-rce-in-langflow-ai/
• [2025-05-06] CISA confirms exploitation of a missing authentication vulnerability in Langflow, a tool for building AI agents.
• [2025-04-22] CVE-2025-3248: Critical remote code execution vulnerability in Langflow, an open-source platform for AI-driven agents and workflows.
• [2025-04-16] POC for CVE-2025-3248 in Langflow versions prior to 1.3.0 allowing remote code execution via crafted HTTP requests.
• [2025-04-13] Langflow AI vulnerability CVE-2025-3248 exploited two weeks after version 1.3.0 release.
• [2025-05-07] CISA warns of active exploitation of critical Langflow vulnerability (CVE-2025-3248) allowing full server takeover.