CVE-2025-34291
Langflow Origin Validation Error Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 4 June 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
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.
- CVSS 4.0
- 9.4 CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 83.63% probability · 100th percentile
- CISA KEV
- Listed 21 May 2026 · due 4 June 2026
- Weakness
- CWE-346
- Affected
- langflow/langflow
- Source
- disclosure@vulncheck.com
CISA notes
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. This vulnerability could affect an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: https://github.com/langflow-ai/langflow ; https://github.com/langflow-ai/langflow/releases/tag/v1.9.3; https://github.com/langflow-ai/langflow/issues/11465#event-25774545848 ; https://nvd.nist.gov/vuln/detail/CVE-2025-34291
References
- https://github.com/langflow-ai/langflowProduct
- https://www.obsidiansecurity.com/blog/cve-2025-34291-critical-account-takeover-and-rce-vulnerability-in-the-langflow-ai-agent-workflow-platformExploit, Mitigation, Third Party Advisory
- https://www.vulncheck.com/advisories/langflow-cors-misconfiguration-to-token-hijack-and-rceThird Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-34291US Government Resource
- https://www.crowdsec.net/vulntracking-report/cve-2025-34291Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.