CVE-2026-42590
Gotenberg: ExifTool group-prefix syntax bypasses dangerous-tag blocklist
- State
- Published
- Severity
- 8.2 High
- Published
- May 14, 2026
- Updated
- May 15, 2026
- Reserved
- Apr 29, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 8.2 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L | GitHub_M |
Weaknesses
- CWE-184 Incomplete List of Disallowed Inputs
Affected Products
| Product | Versions |
|---|---|
gotenberggotenberg |
|
References
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