Risk Letters

Exploited vulnerability

CVE-2025-34291

TLP:CLEAR

Langflow Origin Validation Error Vulnerability

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.

Facts

  • Vendor: Langflow
  • Product: Langflow
  • CVSS: 9.4
  • EPSS (probability of exploitation within 30 days): 92.8 %
  • On CISA's Known Exploited Vulnerabilities list since: 21 May 2026
  • First known exploitation: 21 May 2026
  • CISA's deadline for US federal agencies: 4 June 2026
  • Weakness: CWE-346
  • First seen by Risk Letters: 21 May 2026

Members see which Nordic sectors the flaw hits, and what to do about it.

Get the full brief

Data: NVD (public domain), CISA KEV, FIRST EPSS, MITRE ATT&CK, AlienVault OTX. NVD