Medium
python-werkzeug — security advisory
Werkzeug is a comprehensive WSGI web application library. Prior to 3.1.9, the safe_join function used by send_from_directory can allow a NUL: special-device path because safe_join checks the Windows device name without first removing an empty NTFS ADS marker. The trigger is that an application runs on Windows with NTFS and serves a user-specified path ending in a special device name such as NUL:. The attack mechanism is that a requested path ends in a Windows special device name with an empty ADS marker. The impact is that the special device opens successfully and the file read hangs indefinitely. This issue is fixed in version 3.1.9.
- Products
- python-werkzeug
- Affected versions
- 0.10.4+dfsg1-1ubuntu1, 0.10.4+dfsg1-1ubuntu1.1, 0.10.4+dfsg1-1ubuntu1.2, 0.10.4+dfsg1-1ubuntu1.2+esm1, 0.10.4+dfsg1-1ubuntu1.2+esm2, 0.12.2+dfsg1-2, 0.13+dfsg1-1, 0.14.1+dfsg1-1, 0.14.1+dfsg1-1ubuntu0.1, 0.14.1+dfsg1-1ubuntu0.2, 0.14.1+dfsg1-1ubuntu0.2+esm1, 0.14.1+dfsg1-4, 0.15.6+dfsg1-1, 0.16.0+dfsg1-1, 0.16.1+dfsg1-1ubuntu1, 0.16.1+dfsg1-2, 0.16.1+dfsg1-2ubuntu0.1, 0.16.1+dfsg1-2ubuntu0.2, 1.0.1+dfsg1-2, 2.0.2+dfsg1-1, 2.0.2+dfsg1-1ubuntu0.22.04.1, 2.0.2+dfsg1-1ubuntu0.22.04.2, 2.0.2+dfsg1-1ubuntu0.22.04.3, 2.2.2-3, 3.0.1-1, 3.0.1-2, 3.0.1-3, 3.0.1-3ubuntu0.1, 3.0.1-3ubuntu0.2, 3.1.3-2, 3.1.4-1, 3.1.5-1, 3.1.8-1
- Fixed versions
- Not specified
- CVEs
- CVE-2026-102598
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 02:53 UTC · Revision 1
Source evidence
Werkzeug is a comprehensive WSGI web application library. Prior to 3.1.9, the safe_join function used by send_from_directory can allow a NUL: special-device path because safe_join checks the Windows device name without first removing an empty NTFS ADS marker. The trigger is that an application runs on Windows with NTFS and serves a user-specified path ending in a special device name such as NUL:. The attack mechanism is that a requested path ends in a Windows special device name with an empty ADS marker. The impact is that the special device opens successfully and the file read hangs indefinitely. This issue is fixed in version 3.1.9.
osv:UBUNTU-CVE-2026-102598
python-werkzeug
Fixed versions: Not specified
python-werkzeug
Fixed versions: Not specified
python-werkzeug
Fixed versions: Not specified
python-werkzeug
Fixed versions: Not specified
python-werkzeug
Fixed versions: Not specified
python-werkzeug
Fixed versions: Not specified
python-werkzeug
Fixed versions: Not specified
Complete source record
{
"id": "6258f129245f68b3609c92a33ca3459d346569d926ff5eaf8ca74f0d537f085b",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-102598",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-102598",
"summary": "Werkzeug is a comprehensive WSGI web application library. Prior to 3.1.9, the safe_join function used by send_from_directory can allow a NUL: special-device path because safe_join checks the Windows device name without first removing an empty NTFS ADS marker. The trigger is that an application runs on Windows with NTFS and serves a user-specified path ending in a special device name such as NUL:. The attack mechanism is that a requested path ends in a Windows special device name with an empty ADS marker. The impact is that the special device opens successfully and the file read hangs indefinitely. This issue is fixed in version 3.1.9.",
"evidence": "osv:UBUNTU-CVE-2026-102598",
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{
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{
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{
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"evidence": "/affected/4/versions"
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{
"value": "3.0.1-3",
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{
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{
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{
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{
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],
"severity": "medium",
"structured": {
"id": "UBUNTU-CVE-2026-102598",
"aliases": [
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],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N"
},
{
"type": "Ubuntu",
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],
"modified": "2026-10-17T12:59:43.677206435Z",
"provider": "osv",
"upstream": [
"CVE-2026-102598"
],
"references": [
"https://ubuntu.com/security/CVE-2026-102598",
"https://www.cve.org/CVERecord?id=CVE-2026-102598",
"https://github.com/pallets/werkzeug/commit/8d77320bcdf3a34941ec06dcf16b03c065cd21b6",
"https://github.com/pallets/werkzeug/pull/3309",
"https://github.com/pallets/werkzeug/releases/tag/3.1.9",
"https://github.com/pallets/werkzeug/security/advisories/GHSA-g6x2-hccm-hh4m"
]
},
"related_cves": [
{
"value": "CVE-2026-102598",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 359737,
"published_at": "2026-09-29T16:17:00+00:00"
}