Gotenberg: ExifTool group-prefix syntax bypasses dangerous-tag blocklist_CVE-2026-42590

8.2 / 10

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L

Description

Gotenberg is a Docker-powered stateless API for PDF files. Prior to 8.30.0, The ExifTool metadata write blocklist in Gotenberg can be bypassed using ExifTool's group-prefix syntax, enabling arbitrary file rename, move, hardlink, and symlink creation on the server. ExifTool supports group-prefix syntax where File:FileName is processed identically to FileName -- the prefix is stripped by SetNewValue in Writer.pl before tag matching. The safeKeyPattern regex (^[a-zA-Z0-9\-_.:]+$) allows colons, so prefixed tag names pass validation. Any prefix works: File:FileName, System:Directory, a:HardLink, etc. Additionally, FilePermissions, FileUserID, and FileGroupID pseudo-tags are not blocked at all and can modify file attributes without any prefix. This vulnerability is fixed in 8.30.0.

Basic Information

ID CVE-2026-42590

Source GitHub_M

Published May 14, 2026 at 15:36

Affected Product

Vendor gotenberg

Product gotenberg

Version < 8.30.0

Affected Versions gotenberg gotenberg < 8.30.0

CWE Classification

CWE-184

References

github.com /gotenberg/gotenberg/security/advisories/GHSA-7v3r-m9c8-r855

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