CVE-2025-34291
Langflow: Origin Validation Error
As of , CVE-2025-34291 in Langflow is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch this week.
- Exploited
- Yes: CISA listed it on 21 May 2026
- US federal deadline
- 4 June 202614 days after CISA listed it. US federal civilian agencies must fix it by then.
- Used in ransomware campaigns
- Not known to CISA
- EPSS score
- 0.93Higher than 99% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
- Public exploit
- None foundNeither Metasploit nor Exploit-DB lists one.
- Fix
- Vendor advice: github.comLinks below, from CISA's entry.
What CISA says to do
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA's required action
- github.comThis vulnerability could affect an open-source component, third-party library, protocol, or proprietary implementation that could be used…
- github.com
- github.com
What the flaw is
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.
CISA's 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.
The CVE record's description, from VulnCheck
- CVE published
- 5 December 2025
- Assigned by
- VulnCheck
- CVSS
- 9.4 Critical (CVSS 4.0, from the CNA)
- CWE-346
- Origin Validation Error
- CISA SSVC, exploitation
- active
- CISA SSVC, automatable
- no
- CISA SSVC, technical impact
- total
Timeline
- The CVE record was published.
- CISA added it to its list of exploited vulnerabilities.
- The US federal deadline to fix it.
Langflow: other exploited entries
| Vulnerability | Product | Our group | Listed | Deadline | EPSS |
|---|---|---|---|---|---|
| CVE-2026-0770Inclusion of Functionality from Untrusted Control Sphere | Langflow Langflow | Patch nowForensic triage required by CISA; Metasploit module | 0.63 | ||
| CVE-2026-55255Authorization Bypass Through User-Controlled Key | Langflow Langflow | Patch nowForensic triage required by CISA | 0.01 | ||
| CVE-2025-3248Missing Authentication | Langflow Langflow | Patch this weekRansomware use; Metasploit module; EPSS 0.99 | 0.99 | ||
| CVE-2026-33017Code Injection | Langflow Langflow | Patch this weekMetasploit module | 0.25 |
Read further
- CVE recordcve.org
- NVD entrynvd.nist.gov
- CISA's catalogcisa.gov
- EPSS for this CVEapi.first.org