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
- 92.81% probability · 100th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Listed 21 May 2026 · due 4 June 2026
- Weakness
- CWE-346
- Affected
- langflow/langflow
- Source
- disclosure@vulncheck.com
EPSS moved from 92.8% on 24 September 2026 to 92.8% on 27 October 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
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, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.