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 system without requiring any prior authentication or credentials.

Exploitation Status

A proof-of-concept exploit is publicly available. This vulnerability is not currently listed in CISA's 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 CVSS score of 9.8, no authentication requirement, and a public PoC 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 associations have been established for this vulnerability.

What To Do

Upgrade Langflow to version 1.3.0 or later immediately. Given the critical severity, unauthenticated attack vector, and availability of a public PoC, patching should be treated as urgent. 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 sources only. Organizations should audit logs for unexpected or anomalous POST requests to the validate/code endpoint as a detection signal. Publicly exposed Langflow instances should be considered at elevated risk and prioritized accordingly.