CVE-2025-34291 - Langflow Origin Validation Error Vulnerability

Technical Severity

CVSS v3.1 Metrics

HIGH

8.8 / 10

Minimal Risk Critical

Vector Specification

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation Likelihood

EPSS Prediction

31.20 %

Predictive Probability

Percentile Rank

96.8 th

Documented as more likely to be exploited than 96.8% of known CVEs.

Detection Date

May 21, 2026

Remediation Due

Jun 04, 2026

CISA Catalog Active

Threat Analysis

Langflow contains an origin validation error vulnerability in which an overly permissive CORS configuration combined with a refresh token cookie configured as SameSite=None allows a malicious webpage to perform cross-origin requests that include credentials and successfully call the refresh endpoint. This could allow the attacker to execute arbitrary code and achieve full system compromise via obtained tokens that permit access to authenticated endpoints.

Remediation Directive

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

External Intelligence

This vulnerability could affect an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see:

https://github.com/langflow-ai/langflow

https://github.com/langflow-ai/langflow/releases/tag/v1.9.3

https://github.com/langflow-ai/langflow/issues/11465#event-25774545848

NVD

National Vulnerability Database

https://nvd.nist.gov/vuln/detail/CVE-2025-34291