CVE-2025-34291: Langflow Origin Validation Error Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 21 May 2026, 167 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 92.8%
EPSS score, percentile 99.8 of all scored records
- How severe?
- 9.4 Critical
CVSS v4.0 base score, given by the CNA
- What should I do?
CISA deadline 4 Jun 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.
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected
- 1.6.9 and earlier
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
What to do
Required action, set by CISA
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 due date for this action: 4 June 2026.
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
Linked from CISA's catalog entry
- 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
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | 1.6.9 and earlier |
Versions not listed are: unaffected.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
About this vulnerability
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.
Summary: CISA's KEV catalog, as of 28 Oct 2026.
- CISA added CVE-2025-34291 to its Known Exploited Vulnerabilities (KEV) catalog on 21 May 2026.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 4 Jun 2026.
- The CVE record was published on 5 Dec 2025, 167 days before it was added to KEV.
- The CVE record carries a CVSS v4.0 base score of 9.4 (Critical), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 92.8% (percentile 99.8), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.
Description
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.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
Weakness
- CWE-346: Origin Validation Error
Attack patterns (CAPEC)
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| 5 Dec 2025 | CVE record published |
| 21 May 2026 | Added to CISA KEV |
| 4 Jun 2026 | CISA due date for the required action |
| 8 Oct 2026 | CVE record last updated |
References
More exploited Langflow vulnerabilities
- CVE-2026-0770: Langflow Inclusion of Functionality from Untrusted Control Sphere Vulnerability
- CVE-2026-55255: Langflow Authorization Bypass Through User-Controlled Key Vulnerability
- CVE-2026-33017: Langflow Code Injection Vulnerability
- CVE-2025-3248: Langflow Missing Authentication Vulnerability