CRITICAL Langflow: Langflow CVE-2025-34291 — session hijack to RCE via CORS misconfiguration

Why it matters

A malicious webpage can hijack a logged-in Langflow user's session and then run code on your server, because of a permissive CORS setup plus an unprotected refresh endpoint. Actively exploited. Works even when the victim did nothing but visit a link.

Fix it — 3 steps

Upgrade past 1.6.9 and set CORS allow_origins to your actual domain, never '*' with credentials enabled.
Put the UI behind an authenticating proxy or VPN so drive-by attacks have no session to steal.
Tell your users to log out and rotate API keys if you ran a vulnerable version: sessions may have been hijacked.

Verify it’s fixed

curl -s http://YOUR_SERVER_IP:7860/api/v1/version  # must be > 1.6.9

References

https://www.sentinelone.com/vulnerability-database/cve-2025-34291/

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