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

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-05-14 · updated 2026-06-17
Weakness: CWE-22

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.

Affected products

gotenberg: before 8.32.0 — fixed in 8.32.0

How to fix

Upgrade to a fixed version: gotenberg 8.32.0. Check the vendor advisory for mitigations.

References

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