CVE-2025-34291 — Langflow Origin Validation Error Vulnerability

CVE-2025-34291 (Langflow Langflow) is in the CISA Known Exploited Vulnerabilities catalog since 2026-05-21. Langflow contains an origin validation error vulnerability in which an overly permissive CORS configuration… See the required fix, due date and advisories.

Exploitation status

CVE-2025-34291 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 2026-05-21. 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.

Advisory facts

Vendor or project
Langflow
Affected product
Langflow
Added to CISA KEV
2026-05-21
US federal remediation due date
2026-06-04
Ransomware association
Unknown
EPSS score
—
Weakness (CWE)
CWE-346

Remediation: the 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.

Wording published by CISA for this catalog entry. It is the baseline action, not a decision about your environment: whether this exposure matters for you depends on where the affected component runs, what it is exposed to and who owns it.

From advisory to a decision you can defend

A catalog entry tells you a vulnerability is being exploited somewhere. It does not tell you whether it matters in your estate, who owns the fix, or what evidence an auditor will ask for later. That is the work VulnTrek does: it takes findings from the tools you already run, decides which exposure actually matters, routes it to an owner, keeps remediation human-approved and retains the lineage as evidence.

Sourced from public upstream advisories (CISA KEV, ENISA EUVD, vendor PSIRTs) mirrored daily. Informational only — not a remediation decision, not legal advice, and the absence of a record is not evidence of safety.