Gotenberg: ExifTool group-prefix syntax bypasses dangerous-tag blocklist
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\-_.:]+$) allows colons, so prefixed tag names pass validation. Any prefix works: File:FileName, System:Directory, a:HardLink, etc. Additionally, FilePermissions, FileUserID, and FileGroupID pseudo-tags are not blocked at all and can modify file attributes without any prefix. This vulnerability is fixed in 8.30.0.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-42590
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 3 Nov 2026, 18:53 UTC · Revision 1
Source evidence
Gotenberg: ExifTool group-prefix syntax bypasses dangerous-tag blocklist
core-osv · Original sourcePublished 14 May 2026, 15:36 UTC
Gotenberg is a Docker-powered stateless API for PDF files. Prior to 8.30.0, The ExifTool metadata write blocklist in Gotenberg can be bypassed using ExifTool's group-prefix syntax, enabling arbitrary file rename, move, hardlink, and symlink creation on the server. ExifTool supports group-prefix syntax where File:FileName is processed identically to FileName -- the prefix is stripped by SetNewValue in Writer.pl before tag matching. The safeKeyPattern regex (^[a-zA-Z0-9\-_.:]+$) 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.
osv:CVE-2026-42590
Complete source record
{
"id": "af3a7c1130d47a9e89bedf0a14e84d67f54f1642a9ecdd3070e0b029df187c2f",
"url": "https://osv.dev/vulnerability/CVE-2026-42590",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Gotenberg: ExifTool group-prefix syntax bypasses dangerous-tag blocklist",
"summary": "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.",
"evidence": "osv:CVE-2026-42590",
"products": [],
"severity": "high",
"structured": {
"id": "CVE-2026-42590",
"aliases": [
"CVE-2026-42590",
"GHSA-7v3r-m9c8-r855",
"GO-2026-5234"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/gotenberg/gotenberg",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "a80191a2881184a3529696ebf9cdcd82a0008442"
}
],
"database_specific": {
"extracted_events": [
{
"range": [
{
"introduced": "0"
},
{
"fixed": "8.30.0"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"cpe": "cpe:2.3:a:thecodingmachine:gotenberg:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "0"
},
{
"fixed": "8.30.0"
}
],
"source": "CPE_RANGE"
}
]
}
}
],
"versions": [
"v8.29.1",
"v8.29.0",
"v8.28.0",
"v8.27.0",
"v8.26.0",
"v8.25.1",
"v8.25.0",
"v8.24.0",
"v8.23.2",
"v8.23.1",
"v8.23.0",
"v8.22.0",
"v8.21.1",
"v8.21.0",
"v8.20.1",
"v8.20.0",
"v8.19.1",
"v8.19.0",
"v8.18.0",
"v8.17.3",
"v8.17.2",
"v8.17.1",
"v8.17.0",
"v8.16.0",
"v8.15.3",
"v8.15.2",
"v8.15.1",
"v8.15.0",
"v8.14.1",
"v8.14.0",
"v8.13.0",
"v8.12.0",
"v8.11.1",
"v8.11.0",
"v8.10.0",
"v8.9.2",
"v8.9.1",
"v8.9.0",
"v8.8.1",
"v8.8.0",
"v8.7.0",
"v8.6.0",
"v8.5.1",
"v8.5.0",
"v8.4.0",
"v8.3.0",
"v8.2.2",
"v8.2.1",
"v8.2.0",
"v8.1.0",
"v8.0.3",
"v8.0.2",
"v8.0.1",
"v8.0.0",
"v7.10.1",
"v7.10.0",
"v7.9.2",
"v7.9.1",
"v7.9.0",
"v7.8.3",
"v7.8.2",
"v7.8.1",
"v7.8.0",
"v7.7.2",
"v7.7.1",
"v7.7.0",
"v7.6.2",
"v7.6.1",
"v7.6.0",
"v7.5.4",
"v7.5.3",
"v7.5.2",
"v7.5.1",
"v7.5.0",
"v7.4.3",
"v7.4.2",
"v7.4.1",
"v7.4.0",
"v7.3.1",
"v7.3.0",
"v7.2.0",
"v7.1.1",
"v7.1.0",
"v7.0.7",
"v7.0.6",
"v7.0.5",
"v7.0.4",
"v7.0.3",
"v7.0.2",
"v7.0.1",
"v7.0.0",
"6.4.4",
"6.4.3",
"6.4.2",
"6.4.1",
"6.4.0",
"6.3.1",
"6.3.0",
"6.2.1",
"6.2.0",
"6.1.2",
"6.1.1",
"6.1.0",
"6.0.4",
"6.0.3",
"6.0.2",
"6.0.1",
"6.0.0",
"5.1.0",
"5.0.2",
"5.0.1",
"5.0.0",
"4.4.0",
"4.3.0",
"4.2.0",
"4.1.0",
"4.0.0",
"3.2.0",
"3.1.2",
"3.1.1",
"3.1.0",
"3.0.2",
"3.0.1",
"3.0.0",
"2.0.0",
"1.0.0"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-42590.json"
}
}
],
"modified": "2026-10-28T02:30:31.499228057Z",
"provider": "osv",
"references": [
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42590.json",
"https://github.com/gotenberg/gotenberg/security/advisories/GHSA-7v3r-m9c8-r855",
"https://nvd.nist.gov/vuln/detail/CVE-2026-42590"
],
"provider_metadata": {
"cwe_ids": [
"CWE-184"
],
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42590.json"
}
},
"related_cves": [
{
"value": "CVE-2026-42590",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 498576,
"published_at": "2026-05-14T15:36:30.386+00:00"
}