1. Cleus
  2. Zero-days
  3. CVE-2025-3248
Exploited in the wildUsed by ransomwareServers & business softwareWork IT

CVE-2025-3248 Langflow Langflow: login or permission bypass

In plain words: A door that should be locked is not: part of the system can be reached without a valid login or permission. The attacker gets in as a user or administrator without knowing a password.

Confirmed exploited by CISA on · US federal patch deadline May 26, 2025

What to do

  1. Install Langflow's security update for Langflow. If no update exists, follow the vendor's workaround or stop using the product until one ships.
  2. Keep a list of every internet-facing server you run so nothing is forgotten.
  3. Patch anything in this catalog first, ahead of normal patch cycles.
  4. Put admin and file-transfer apps behind a VPN or single sign-on instead of the open internet.

Who is affected

Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.

What's at risk: Mass data theft and ransomware: a single flaw in a file-transfer or email server has exposed thousands of organisations at once.

The details

Official name
Langflow Missing Authentication Vulnerability
Product
Langflow Langflow
CISA description
Langflow contains a missing authentication vulnerability in the /api/v1/validate/code endpoint that allows a remote, unauthenticated attacker to execute arbitrary code via crafted HTTP requests.
Type of flaw
Login or permission bypass (CWE-306)
Confirmed exploited
May 5, 2025 — known to be used in ransomware attacks
US federal patch deadline
May 26, 2025

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Answering about CVE-2025-3248 ·

Questions about CVE-2025-3248

Is CVE-2025-3248 being exploited?

Yes. CISA added CVE-2025-3248 to its Known Exploited Vulnerabilities catalog on May 5, 2025, which means there is reliable evidence of real-world attacks, including by ransomware groups.

How do I fix CVE-2025-3248?

Install Langflow's security update for Langflow. If no update exists, follow the vendor's workaround or stop using the product until one ships. Keep a list of every internet-facing server you run so nothing is forgotten.

Am I affected by CVE-2025-3248?

Only if you use Langflow Langflow. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.

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