Medium
jupyterhub — security advisory
JupyterHub is software that allows users to create a multi-user server for Jupyter notebooks. Prior to 5.5.0, invalid input to form-based login authenticators can place an unbounded attacker-controlled username in failed-login logs, allowing an unauthenticated attacker to consume logging and storage resources. This issue is fixed in version 5.5.0.
- Products
- jupyterhub
- Affected versions
- 2.0.0+ds1-1, 2.0.0+ds1-2, 3.0.0+ds1-1, 5.2.1+ds1-4, 5.2.1+ds1-5
- Fixed versions
- Not specified
- CVEs
- CVE-2026-54338
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 02:28 UTC · Revision 1
Source evidence
JupyterHub is software that allows users to create a multi-user server for Jupyter notebooks. Prior to 5.5.0, invalid input to form-based login authenticators can place an unbounded attacker-controlled username in failed-login logs, allowing an unauthenticated attacker to consume logging and storage resources. This issue is fixed in version 5.5.0.
osv:UBUNTU-CVE-2026-54338
jupyterhub
Fixed versions: Not specified
jupyterhub
Fixed versions: Not specified
jupyterhub
Fixed versions: Not specified
jupyterhub
Fixed versions: Not specified
Complete source record
{
"id": "0a46c6ac0dc9e22e4813dee6a6db7cde53db5af5fdbdf9fc2e99a46c05fb01f1",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-54338",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-54338",
"summary": "JupyterHub is software that allows users to create a multi-user server for Jupyter notebooks. Prior to 5.5.0, invalid input to form-based login authenticators can place an unbounded attacker-controlled username in failed-login logs, allowing an unauthenticated attacker to consume logging and storage resources. This issue is fixed in version 5.5.0.",
"evidence": "osv:UBUNTU-CVE-2026-54338",
"products": [
{
"name": {
"value": "jupyterhub",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.0.0+ds1-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.0.0+ds1-2",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "jupyterhub",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3.0.0+ds1-1",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "jupyterhub",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "5.2.1+ds1-4",
"evidence": "/affected/2/versions"
},
{
"value": "5.2.1+ds1-5",
"evidence": "/affected/2/versions"
}
]
},
{
"name": {
"value": "jupyterhub",
"evidence": "/affected/3/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "5.2.1+ds1-4",
"evidence": "/affected/3/versions"
}
]
}
],
"severity": "medium",
"structured": {
"id": "UBUNTU-CVE-2026-54338",
"aliases": [
"UBUNTU-CVE-2026-54338"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "jupyterhub",
"purl": "pkg:deb/ubuntu/jupyterhub?arch=source&distro=jammy",
"ecosystem": "Ubuntu:22.04:LTS"
},
"versions": [
"2.0.0+ds1-1",
"2.0.0+ds1-2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-54338.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "jupyterhub",
"binary_version": "2.0.0+ds1-2"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "jupyterhub",
"purl": "pkg:deb/ubuntu/jupyterhub?arch=source&distro=noble",
"ecosystem": "Ubuntu:24.04:LTS"
},
"versions": [
"3.0.0+ds1-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-54338.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "jupyterhub",
"binary_version": "3.0.0+ds1-1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "jupyterhub",
"purl": "pkg:deb/ubuntu/jupyterhub?arch=source&distro=stonking",
"ecosystem": "Ubuntu:26.10"
},
"versions": [
"5.2.1+ds1-4",
"5.2.1+ds1-5"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-54338.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "jupyterhub",
"binary_version": "5.2.1+ds1-5"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "jupyterhub",
"purl": "pkg:deb/ubuntu/jupyterhub?arch=source&distro=resolute",
"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"5.2.1+ds1-4"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-54338.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "jupyterhub",
"binary_version": "5.2.1+ds1-4"
}
]
}
}
],
"modified": "2026-10-17T12:58:35.443553283Z",
"provider": "osv",
"upstream": [
"CVE-2026-54338"
],
"references": [
"https://ubuntu.com/security/CVE-2026-54338",
"https://www.cve.org/CVERecord?id=CVE-2026-54338",
"https://github.com/jupyterhub/jupyterhub/commit/d6dc595f84b7509969686da31d87d6d69e7fce0a",
"https://github.com/jupyterhub/jupyterhub/security/advisories/GHSA-p43p-whwx-q52h"
]
},
"related_cves": [
{
"value": "CVE-2026-54338",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 358821,
"published_at": "2026-08-07T21:17:00+00:00"
}