Gotenberg: Unauthenticated RCE via ExifTool Metadata Key Injection
Title source: cnaExploitation Summary
CVE-2026-42589 has been observed exploited in the wild (reported by VulnCheck KEV). EIP tracks 1 public exploit from researchers including fineman999. A Nuclei detection template is also available.
AI-analyzed exploit summary This repository contains a functional exploit PoC for CVE-2026-42589, demonstrating unauthenticated RCE in Gotenberg via metadata key injection in the /forms/pdfengines/metadata/write endpoint. The exploit uses a timing-based check with a sleep command to verify vulnerability.
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.
Exploits (1)
This repository contains a functional exploit PoC for CVE-2026-42589, demonstrating unauthenticated RCE in Gotenberg via metadata key injection in the /forms/pdfengines/metadata/write endpoint. The exploit uses a timing-based check with a sleep command to verify vulnerability.
Nuclei Templates (1)
References (1)
Scores
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H