CVE-2025-34291
Origin Validation Error in Langflow. CISA confirmed attackers exploit it and added it to its Known Exploited Vulnerabilities catalog on 21 May 2026.
- Product
- Langflow
- Added to CISA's catalog
- Federal fix-by date
- Ransomware
- No known use in ransomware campaigns
- Vendor advisories
- Sources
- CISA’s catalog, NVD entry
CISA’s description.
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.
More from Langflow this year.
- CVE-2026-0770 Inclusion of Functionality from Untrusted Control Sphere, added
- CVE-2026-55255 Authorization Bypass Through User-Controlled Key, added
- CVE-2026-33017 Code Injection, added
Every flaw CISA confirmed exploited in the last 30 days is on the exploit watch. This is not security advice. Check the vendor’s advisory before acting. From CISA’s catalog of 4 November 2026.