Exploited· due 2026-06-04
CVE-2025-34291
Langflow Langflow
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.
Exploitation status
- CISA has confirmed this is being exploited in the wild. That is an observation of real attacks, not a prediction.
- US federal civilian agencies are required to remediate it by 2026-06-04. That deadline does not bind private companies, but it is a reasonable benchmark for how urgently CISA views it.
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.
CISA’s wording, unedited.
Scoring
- CVSS
- Not yet scored
Dates
- Published
- 2026-05-21
- Added to KEV
- 2026-05-21
- Remediation due
- 2026-06-04
- Sources
- CISA KEV