CVE-2025-3248 -- CVSS 9.8 Vulnerability Briefing

CVE-2025-3248 | CVSS 9.8 (Critical) | Exploit: PoC available

What Is It

CVE-2025-3248 is an unauthenticated remote code execution vulnerability in Langflow's HTTP API, specifically the /api/v1/validate/code endpoint, affecting all versions prior to 1.3.0.

Technical Detail

The flaw is a code injection weakness in the code validation endpoint, which fails to properly sanitize or restrict user-supplied input before executing it server-side. A remote, unauthenticated attacker can craft an HTTP request to this endpoint and achieve arbitrary code execution in the context of the Langflow server process. Successful exploitation grants full control over the host, including the ability to exfiltrate data, establish persistence, or pivot to connected systems.

Exploitation Status

A proof-of-concept exploit is publicly available. This vulnerability is not currently listed in the CISA Known Exploited Vulnerabilities catalog, meaning active in-the-wild exploitation has not been formally confirmed by CISA as of this writing. However, the combination of a public PoC, unauthenticated attack vector, and critical CVSS score of 9.8 significantly elevates the risk of exploitation in the near term.

Who Is Targeting This

No specific threat actor attribution at this time. Neither confirmed nor reported threat actor activity has been associated with this CVE in available intelligence sources.

What To Do

Upgrade Langflow to version 1.3.0 or later immediately. Given the unauthenticated nature of the vulnerability and the availability of a public PoC, this should be treated as a high-priority patch. If immediate patching is not possible, restrict network access to the Langflow API, particularly the /api/v1/validate/code endpoint, using firewall rules or reverse proxy controls to limit exposure to trusted IP ranges only. Publicly exposed Langflow instances should be considered at elevated risk and audited for signs of compromise, including unexpected process execution, outbound connections, or new user accounts. Monitor HTTP server logs for anomalous POST requests to the validation endpoint as a detection signal.