CVE-2025-34291: Langflow Langflow exploited

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

What it is

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.

Description quoted from the CVE record (assigned by VulnCheck, published 2025-12-05).

Weakness: CWE-346 Origin Validation Error

How it can be exploited

Exploitable over the network with low attack complexity with no special attack requirements needing no privileges and a user must take an action. Impact: confidentiality high, integrity high, availability high. 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

CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: no. Technical impact: total.

On CISA KEV since: 2026-05-21
US federal deadline: 2026-06-04
Ransomware use: Not known

Public exploit evidence (Exploit Observer)

Also known as: BDU:2026-14691, CNNVD-202512-629, EUVD-2025-201507, GHSA-577h-p2hh-v4mv

VEDAS cluster: VEDAS:FLORACHAMPION

Exploit Observer links 8 pieces of public exploit code or detection modules that name this CVE or one of its aliases.

Exploit code and modules (8)

Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.

Nuclei template: https://raw.githubusercontent.com/projectdiscovery/nuclei-templates/main/http/cves/2025/CVE-2025-34291.yaml
Code repository: https://github.com/amnnrth/cve-2025-34291_cors_security_scanner
Code repository: https://github.com/ridhinva/cve-2025-34291-langflow-scanner
Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/nuclei/2025/CVE-2025-34291.yaml
Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/nuclei/2025/CVE-2025-34291.yaml
Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/suricata/2025/CVE-2025-34291.rules
Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/suricata/2025/CVE-2025-34291.rules
Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/suricata/2025/CVE-2025-34291.rules

Research and write-ups (2)

Research or write-up: https://www.crowdsec.net/vulntracking-report/cve-2025-34291
Research or write-up: https://www.obsidiansecurity.com/blog/cve-2025-34291-critical-account-takeover-and-rce-vulnerability-in-the-langflow-ai-agent-workflow-platform

Vulnerability databases and vendor advisories (8)

Catalogue entries, not exploit evidence.

Vulnerability database or vendor advisory: https://euvd.enisa.europa.eu/enisa/EUVD-2025-201507
Vulnerability database or vendor advisory: https://github.com/advisories/GHSA-577h-p2hh-v4mv
Vulnerability database or vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2025-34291
Vulnerability database or vendor advisory: https://osv.dev/vulnerability/CVE-2025-34291
Vulnerability database or vendor advisory: https://osv.dev/vulnerability/GHSA-577h-p2hh-v4mv
Vulnerability database or vendor advisory: https://osv.dev/vulnerability/ROOT-APP-PYPI-CVE-2025-34291
Vulnerability database or vendor advisory: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-34291
Vulnerability database or vendor advisory: https://www.cnnvd.org.cn/home/globalSearch?keyword=CNNVD-202512-629

8 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.

VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.

Live scores

EPSS: 0.928
very likely to be attacked soon
VEDAS: 0.980
strong exploit evidence
On CISA KEV: Yes, since 2026-05-21
Detection rule: Nuclei · Suricata

EPSS (chance of attack)

VEDAS (exploit evidence)

Thin horizontal line: the “likely” (EPSS 0.10) or “strong” (VEDAS 0.90) threshold. Shaded “no data” areas are periods when cve-scores did not publish. The vertical line is the day CISA added it to its exploited list.

VEDAS flagged this bug about 130 days before CISA confirmed attacks.

Who is affected

Product	Affected	Not affected
Langflow Langflow	up to and including 1.6.9	Not stated

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

Exploit Observer also maps it to: langflow langflow, pypi langflow, сообщество_свободного_программного_обеспечения langflow.

How to fix it

CISA 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.

Vendor guidance:

How to detect it

Nuclei template (active check)

Langflow - Remote Code Execution
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.

Name and description quoted from the template, written by VEDAS.

The template sends 2 requests (GET /, OPTIONS /api/v1/refresh); it decides using status, word matchers. Severity in the template: critical. Marked as not yet verified against a live vulnerable target.

Run it against a host you own or are authorised to test:

bash

nuclei -u https://your-host -t CVE-2025-34291.yaml

Show the template (58 lines)

yaml

id: CVE-2025-34291

info:
  name: "Langflow - Remote Code Execution"
  author: vedas-arpsyndicate
  severity: critical
  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.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2025-34291&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=langflow&match=exact
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
    cvss-score: 9.4
    cve-id: CVE-2025-34291
    cwe-id: CWE-942
  metadata:
    verified: false
  tags: cve,cve2025,langflow,cors,misconfig,vuln,oss,vkev,kev
flow: http(1) && http(2)

http:
  - raw:
      - |
        GET / HTTP/1.1
        Host: {{Hostname}}

    matchers:
      - type: word
        part: body
        words:
          - "Langflow"
        internal: true

  - raw:
      - |
        OPTIONS /api/v1/refresh HTTP/1.1
        Host: {{Hostname}}
        Origin: https://scanme.sh
        Access-Control-Request-Method: POST
        Access-Control-Request-Headers: content-type

    matchers-condition: and
    matchers:
      - type: word
        part: header
        words:
          - "Access-Control-Allow-Origin: https://scanme.sh"
          - "Access-Control-Allow-Credentials: true"
        condition: and

      - type: status
        part: header
        status:
          - 200

CVE-2025-34291.yaml on GitHub

Suricata rules (network detection)

1 rule that alert on traffic matching this exploit: VEDAS CVE-2025-34291 Langflow - Remote Code Execution. Add them to your Suricata rule set and reload.

Show the rules

suricata

alert http $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"VEDAS CVE-2025-34291 Langflow - Remote Code Execution"; flow:established,to_server; http.uri; content:"refresh"; nocase; fast_pattern; classtype:web-application-attack; reference:cve,CVE-2025-34291; reference:url,https://www.exploit.observer/?keyword=CVE-2025-34291&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=langflow&match=exact; sid:1011502; rev:1;)

CVE-2025-34291.rules on GitHub

References

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer, vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.