Langflow Origin Validation Error Vulnerability
Langflow — Langflow
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.
9.4
78.9%
Vector breakdown
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- None
- User interaction
- Passive
- Confidentiality (Vulnerable System)
- High
- Integrity (Vulnerable System)
- High
- Availability (Vulnerable System)
- High
- Confidentiality (Subsequent System)
- High
- Integrity (Subsequent System)
- High
- Availability (Subsequent System)
- High
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
- Published
- Dec 5, 2025
- Modified
- Jul 14, 2026
- Added to KEV
- May 21, 2026
- Federal patch due
- Jun 4, 2026
CISA 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.
Weakness classification
Proof-of-concept & exploitation references
Weaponization
Public repositories whose name or description references CVE-2025-34291, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit - cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.
No public GitHub repositories referencing CVE-2025-34291 were found at last check. Absence here is not proof no exploit exists - see the references below for vendor advisories and write-ups.
References
Frequently asked questions
What is CVE-2025-34291?
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.
How severe is CVE-2025-34291?
CVE-2025-34291 has a CVSS base score of 9.4 out of 10 (CVSS 4.0).
Is CVE-2025-34291 actively exploited in the wild?
Yes. CVE-2025-34291 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added May 21, 2026, meaning CISA has confirmed evidence of active exploitation.
What is the EPSS score for CVE-2025-34291?
78.9% - meaning FIRST.org's EPSS model estimates a 78.9% probability this vulnerability will be exploited in the wild within 30 days (100% percentile among all scored CVEs).
Is there exploit tooling available for CVE-2025-34291?
Yes - a public Nuclei template referencing CVE-2025-34291 exist in public repositories we checked.
What type of vulnerability is CVE-2025-34291?
CVE-2025-34291 is classified under CWE-346 (CWE-346 Origin Validation Error).
Cross-checked against
Impactr finds and proves whether CVE-2025-34291 - or flaws like it - are actually reachable in your own web apps and APIs, with a reproducible exploit as evidence.
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