CVE-2025-34291

Published Dec 5, 2025

Last updated 18 days ago

Exploit known CVSS critical 9.4

Langflow

Cloud

API

Overview

AI description

Automated description summarized from trusted sources.

CVE-2025-34291 is a chained vulnerability affecting Langflow versions up to and including 1.6.9, which can lead to account takeover and remote code execution (RCE). This flaw stems from an overly permissive Cross-Origin Resource Sharing (CORS) configuration, where `allow_origins='*'` is combined with `allow_credentials=True`. This misconfiguration, coupled with a refresh token cookie set to `SameSite=None`, allows a malicious webpage to make cross-origin requests that include user credentials. By successfully calling the refresh endpoint, an attacker can obtain valid access and refresh token pairs for a victim's session. These acquired tokens can then be used to access authenticated endpoints, including those designed for code execution, ultimately enabling the attacker to achieve remote code execution. The vulnerability also involves a lack of CSRF protection on the token refresh endpoint and a code validation endpoint that permits code execution by design. Active exploitation of this vulnerability has been observed.

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.
Source: disclosure@vulncheck.com
NVD status: Analyzed
Products: langflow

Risk scores

CVSS 4.0

Type: Secondary
Base score: 9.4
Impact score: -
Exploitability score: -
Vector string: 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Severity: CRITICAL

CVSS 3.1

Type: Primary
Base score: 8.8
Impact score: 5.9
Exploitability score: 2.8
Vector string: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity: HIGH

Known exploits

Data from CISA

Vulnerability name: Langflow Origin Validation Error Vulnerability
Exploit added on: May 21, 2026
Exploit action due: Jun 4, 2026
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.

Weaknesses

disclosure@vulncheck.com: CWE-346

Hype score: Not currently trending

Configurations

[
  {
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:langflow:langflow:*:*:*:*:*:*:*:*",
            "matchCriteriaId": "1D74DC53-9772-4172-822E-3E29E5A4DDC9",
            "versionEndIncluding": "1.6.9",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ]
  }
]

References

Sources include official advisories and independent security research.