Langflow Missing Authentication Vulnerability (CVE-2025-3248)

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.

Published Apr 7, 2025 · Updated May 29, 2026

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Why patchRisk explained in plain English

Worst-case scenarioIf unpatched

A remote attacker, without authentication, can achieve full data confidentiality loss, arbitrary modification of data, complete denial of service or system unavailability. Federal agencies are required to remediate by 2025-05-26 under CISA BOD 22-01.

How the attack worksNo clicks needed

This is a Missing Authentication for Critical Function (CWE-306) vulnerability in Langflow Langflow. Langflow versions prior to 1.3.0 are susceptible to code injection in the /api/v1/validate/code endpoint. A remote and unauthenticated attacker can send crafted HTTP requests to execute arbitrary code. Exploitation requires remote network access, low attack complexity, no authentication required, and no user interaction required.

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Phishing link

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Malicious file

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Server compromised

Am I affected?Quick check

Probably yes if any of these apply:

●IT Security

●Running langflow: v < 1.3.0

Real-world incidentsWhat we've seen

Active exploitation documented in the wild. Threat-research write-up: https://www.horizon3.ai/attack-research/disclosures/unsafe-at-any-speed-abusing-python-exec-for-unauth-rce-in-langflow-ai/

How to patch

Manual remediation steps

Apply the Vendor Patch

This vulnerability is in the CISA Known Exploited Vulnerabilities catalog — apply the vendor's security update as soon as possible.

CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.