Langflow <=1.6.9 CORS + SameSite Misconfig Enables Account Takeover & RCE
CVE-2025-34291 Published on December 5, 2025
Langflow <= 1.6.9 CORS Misconfiguration to Token Hijack & RCE
Langflow versions up to and including 1.6.9 contain a chained vulnerability that enables account takeover and remote code execution. An overly permissive CORS configuration (allow_origins='*' with allow_credentials=True) 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. An attacker-controlled origin can therefore obtain fresh access_token / refresh_token pairs for a victim session. Obtained tokens permit access to authenticated endpoints including built-in code-execution functionality allowing the attacker to execute arbitrary code and achieve full system compromise.
Known Exploited Vulnerability
This Langflow Origin Validation Error Vulnerability is part of CISA's list of Known Exploited Vulnerabilities. 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.
The following remediation steps are recommended / required by June 4, 2026: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Weakness Type
Origin Validation Error
The software does not properly verify that the source of data or communication is valid.
Products Associated with CVE-2025-34291
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Affected Versions
Langflow:- Before and including 1.6.9 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.