High
jupyter-server — security advisory
A path traversal vulnerability exists in jupyter-server version 2.17.0 due to an incorrect root directory boundary check in the _get_os_path() function within jupyter_server/services/contents/fileio.py. The check uses startswith(root) without appending a trailing path separator, allowing sibling directories with names starting with the same prefix as root_dir to bypass the check. Additionally, the to_os_path() function in utils.py does not strip ".." from path parts, enabling traversal sequences to bypass the vulnerable check. This vulnerability can lead to unauthorized read/write access to files in sibling directories, potentially exposing sensitive data in shared hosting environments.
- Products
- jupyter-server
- Affected versions
- 1.13.1-1, 1.2.2-1, 1.23.3-1, 1.23.3-2, 2.14.2-5, 2.15.0-1, 2.17.0-1, 2.20.0-3
- Fixed versions
- Not specified
- CVEs
- CVE-2026-5422
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 02:45 UTC · Revision 1
Source evidence
A path traversal vulnerability exists in jupyter-server version 2.17.0 due to an incorrect root directory boundary check in the _get_os_path() function within jupyter_server/services/contents/fileio.py. The check uses startswith(root) without appending a trailing path separator, allowing sibling directories with names starting with the same prefix as root_dir to bypass the check. Additionally, the to_os_path() function in utils.py does not strip ".." from path parts, enabling traversal sequences to bypass the vulnerable check. This vulnerability can lead to unauthorized read/write access to files in sibling directories, potentially exposing sensitive data in shared hosting environments.
osv:UBUNTU-CVE-2026-5422
jupyter-server
Fixed versions: Not specified
jupyter-server
Fixed versions: Not specified
jupyter-server
Fixed versions: Not specified
jupyter-server
Fixed versions: Not specified
jupyter-server
Fixed versions: Not specified
Complete source record
{
"id": "016e7d9f290a3d593f28443b444d093557c9a28b99f1a6536b5e573cb0bb6924",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-5422",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-5422",
"summary": "A path traversal vulnerability exists in jupyter-server version 2.17.0 due to an incorrect root directory boundary check in the _get_os_path() function within jupyter_server/services/contents/fileio.py. The check uses startswith(root) without appending a trailing path separator, allowing sibling directories with names starting with the same prefix as root_dir to bypass the check. Additionally, the to_os_path() function in utils.py does not strip \"..\" from path parts, enabling traversal sequences to bypass the vulnerable check. This vulnerability can lead to unauthorized read/write access to files in sibling directories, potentially exposing sensitive data in shared hosting environments.",
"evidence": "osv:UBUNTU-CVE-2026-5422",
"products": [
{
"name": {
"value": "jupyter-server",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
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"affected_versions": [
{
"value": "1.2.2-1",
"evidence": "/affected/0/versions"
},
{
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}
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{
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{
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}
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{
"name": {
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"affected_versions": [
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"evidence": "/affected/3/versions"
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{
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"evidence": "/affected/3/versions"
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{
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{
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}
]
}
],
"severity": "high",
"structured": {
"id": "UBUNTU-CVE-2026-5422",
"aliases": [
"UBUNTU-CVE-2026-5422"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N"
},
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
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"events": [
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],
"package": {
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"purl": "pkg:deb/ubuntu/jupyter-server?arch=source&distro=jammy",
"ecosystem": "Ubuntu:22.04:LTS"
},
"versions": [
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"1.13.1-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-5422.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "jupyter-server",
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{
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{
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"package": {
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"versions": [
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"purl": "pkg:deb/ubuntu/jupyter-server?arch=source&distro=questing",
"ecosystem": "Ubuntu:25.10"
},
"versions": [
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],
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},
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{
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},
{
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},
{
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"purl": "pkg:deb/ubuntu/jupyter-server?arch=source&distro=stonking",
"ecosystem": "Ubuntu:26.10"
},
"versions": [
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"2.20.0-3"
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"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
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"2.17.0-1"
],
"database_specific": {
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},
"ecosystem_specific": {
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}
],
"modified": "2026-10-17T12:59:03.883385183Z",
"provider": "osv",
"upstream": [
"CVE-2026-5422"
],
"references": [
"https://ubuntu.com/security/CVE-2026-5422",
"https://www.cve.org/CVERecord?id=CVE-2026-5422",
"https://huntr.com/bounties/24a36953-6490-466f-8cb2-a90d1ca56e0f"
]
},
"related_cves": [
{
"value": "CVE-2026-5422",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/1/score"
},
"source_id": "core-osv",
"document_id": 359249,
"published_at": "2026-06-02T10:16:00+00:00"
}