CVE-2026-42593: Gotenberg: Arbitrary PDF read via stampExpression and watermarkExpression in merge, split, and convert routes

Vulnerability summary

CVE-2026-42593 is a medium (CVSS 5.3) vulnerability in gotenberg. EPSS estimates a 0.31% chance of exploitation in the next 30 days, higher than 24% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 14-05-2026
   PublishedVulnerability first disclosed.
2. 14-05-2026
   Last modifiedVulnerability information updated.

Description

Gotenberg is a Docker-powered stateless API for PDF files. Prior to 8.32.0, pdfengines/merge, pdfengines/split, libreoffice/convert, chromium/convert/url, chromium/convert/html, and chromium/convert/markdown accept stampSource=pdf + stampExpression=/path and watermarkSource=pdf + watermarkExpression=/path from anonymous callers. The dedicated stamp/watermark routes require an uploaded file when the source type is image or pdf; these six routes only overwrite the expression when a file is uploaded, leaving the user-controlled path intact when no file is attached. pdfcpu opens the path and composites its pages onto the output PDF, which returns to the caller. An attacker reads any PDF the Gotenberg process can access on the container filesystem. This vulnerability is fixed in 8.32.0.

• CWE-22Improper Limitation of a Pathname to a Restricted DirectoryThe product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
• CWE-73External Control of File Name or PathThe product allows user input to control or influence paths or file names that are used in filesystem operations.