CVE-2025-34291 — Langflow Origin Validation Error Vulnerability

Overview

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 ...

Vulnerability details

CVE ID

CVE-2025-34291

Vulnerability

Langflow Origin Validation Error Vulnerability

Vendor

Langflow

Affected products

Langflow: Langflow

Severity

HIGH

Exploitation status

Actively exploited in the wild (CISA KEV)

EPSS score

25.2% probability of exploitation in 30 days · 98th percentile

Published

2026-05-21

Remediation guidance

CVE-2025-34291 is in CISA's Known Exploited Vulnerabilities (KEV) catalog — U.S. federal civilian agencies are required to remediate it under Binding Operational Directive 22-01. Treat it as a priority for every environment.

Apply the vendor's official security update for Langflow the affected product as soon as possible. Where a patch is unavailable, apply vendor mitigations or isolate/segment exposed systems.

FIRST EPSS estimates a 25.2% probability that CVE-2025-34291 will be exploited within the next 30 days (98th percentile of all CVEs) — useful for risk-based patch sequencing.

Hunt for indicators of compromise tied to this vulnerability and confirm logging/EDR coverage on affected assets.

Authoritative references

• NVD — National Vulnerability Database
• MITRE CVE Record
• CISA Known Exploited Vulnerabilities Catalog
• FIRST EPSS — Exploit Prediction Scoring

Related actively-exploited CVEs — Langflow