vnu — security advisory
Nu Html Checker (validator.nu) contains a restriction bypass that allows remote attackers to make the server perform arbitrary HTTP/HTTPS requests to internal resources, including localhost services. While the validator implements hostname-based protections to block direct access to localhost and 127.0.0.1, these controls can be bypassed using DNS rebinding techniques or domains that resolve to loopback addresses.This issue affects The Nu Html Checker (vnu): latest (commit 23f090a11bab8d0d4e698f1ffc197a4fe226a9cd).
- Products
- vnu
- Affected versions
- 23.4.11+dfsg-5, 26.5.2.1+dfsg-1, 26.5.2.1+dfsg-2, 26.8.15.1+dfsg-1
- Fixed versions
- Not specified
- CVEs
- CVE-2025-15104
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 01:25 UTC · Revision 1
Source evidence
Nu Html Checker (validator.nu) contains a restriction bypass that allows remote attackers to make the server perform arbitrary HTTP/HTTPS requests to internal resources, including localhost services. While the validator implements hostname-based protections to block direct access to localhost and 127.0.0.1, these controls can be bypassed using DNS rebinding techniques or domains that resolve to loopback addresses.This issue affects The Nu Html Checker (vnu): latest (commit 23f090a11bab8d0d4e698f1ffc197a4fe226a9cd).
osv:UBUNTU-CVE-2025-15104
vnu
Fixed versions: Not specified
Complete source record
{
"id": "3b89d935155cd5010caa39d150dbe2ce2db36c50a8df489293ad289998248fb0",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2025-15104",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2025-15104",
"summary": "Nu Html Checker (validator.nu) contains a restriction bypass that allows remote attackers to make the server perform arbitrary HTTP/HTTPS requests to internal resources, including localhost services. While the validator implements hostname-based protections to block direct access to localhost and 127.0.0.1, these controls can be bypassed using DNS rebinding techniques or domains that resolve to loopback addresses.This issue affects The Nu Html Checker (vnu): latest (commit 23f090a11bab8d0d4e698f1ffc197a4fe226a9cd).",
"evidence": "osv:UBUNTU-CVE-2025-15104",
"products": [
{
"name": {
"value": "vnu",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "23.4.11+dfsg-5",
"evidence": "/affected/0/versions"
},
{
"value": "26.5.2.1+dfsg-1",
"evidence": "/affected/0/versions"
},
{
"value": "26.5.2.1+dfsg-2",
"evidence": "/affected/0/versions"
},
{
"value": "26.8.15.1+dfsg-1",
"evidence": "/affected/0/versions"
}
]
}
],
"severity": "medium",
"structured": {
"id": "UBUNTU-CVE-2025-15104",
"aliases": [
"UBUNTU-CVE-2025-15104"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N"
},
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "vnu",
"purl": "pkg:deb/ubuntu/vnu?arch=source&distro=stonking",
"ecosystem": "Ubuntu:26.10"
},
"versions": [
"23.4.11+dfsg-5",
"26.5.2.1+dfsg-1",
"26.5.2.1+dfsg-2",
"26.8.15.1+dfsg-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2025/UBUNTU-CVE-2025-15104.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libvnu-java",
"binary_version": "26.8.15.1+dfsg-1"
},
{
"binary_name": "libvnu-java-common",
"binary_version": "26.8.15.1+dfsg-1"
},
{
"binary_name": "vnu",
"binary_version": "26.8.15.1+dfsg-1"
},
{
"binary_name": "vnu-client",
"binary_version": "26.8.15.1+dfsg-1"
},
{
"binary_name": "vnu-common",
"binary_version": "26.8.15.1+dfsg-1"
},
{
"binary_name": "vnu-jetty12",
"binary_version": "26.8.15.1+dfsg-1"
},
{
"binary_name": "vnu-server",
"binary_version": "26.8.15.1+dfsg-1"
},
{
"binary_name": "vnu-tomcat11",
"binary_version": "26.8.15.1+dfsg-1"
}
]
}
}
],
"modified": "2026-10-17T12:56:48.368570140Z",
"provider": "osv",
"upstream": [
"CVE-2025-15104"
],
"references": [
"https://ubuntu.com/security/CVE-2025-15104",
"https://www.cve.org/CVERecord?id=CVE-2025-15104",
"https://github.com/validator/validator/issues/2033",
"https://github.com/validator/validator/commit/b95c4190258db2769cff67cc09d323432bd7a99e"
]
},
"related_cves": [
{
"value": "CVE-2025-15104",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 356331,
"published_at": "2026-01-16T14:15:00+00:00"
}