CVE-2026-42589: Gotenberg: Unauthenticated RCE via ExifTool Metadata Key Injection

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 3.0% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-05-14 · updated 2026-06-17
Weakness: CWE-78

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. 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.

Affected products

gotenberg: before 8.31.0 — fixed in 8.31.0

How to fix

Upgrade to a fixed version: gotenberg 8.31.0. Check the vendor advisory for mitigations.

References

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