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Fencer Vulns
critical 9.8

CVE-2026-42589 json

Gotenberg: Unauthenticated RCE via ExifTool Metadata Key Injection

published 2026-05-07 6 mo ago modified 2026-06-25 4 mo ago also GHSA-rqgh-gxv4-6657 , GO-2026-5636 , EUVD-2026-30311

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
3.0%
EPSS 3.0% chance of exploitation in 30 days, percentile 87%
public exploits
0
none known, plus a Nuclei check

Summary

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.

Patch / fix

  • thecodingmachine gotenberg 8.31.0
  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
total
Assessed
5 mo ago

Exploit prediction

3.01% chance of exploitation in the next 30 days, higher than 87% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • Nuclei template Gotenberg - Command Injection nuclei detection template
  • github.com https://github.com/gotenberg/gotenberg/security/advisories/GHSA-rqgh-gxv4-6657 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
GitHub 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
go github.com/gotenberg/gotenberg/v8
1 listed version
all versions
 no fix listed
go github.com/gotenberg/gotenberg/v7
all versions
 no fix listed

Affected products

  • gotenberg gotenberg

Classification

Weakness
  • CWE-78 Improper Neutralization of Special Elements used in an OS Command

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.