LowFix available
adminer — security advisory
Adminer 4.6.0 through 5.5.0 (fixed in 5.5.1) contains an incomplete fix for a prior X-Forwarded-Prefix vulnerability (GHSA-8478-xrj3-h9c2). The validation guard (bootstrap.inc.php) only rejects prefixes matching ^/[^/], blocking //evil.com but allowing values such as /\evil.com whose second character is a backslash. Because browsers normalize backslash to forward slash, a network-path reference survives into REQUEST_URI and reaches cookie_path(), affecting the Set-Cookie Path attribute. Exploitation requires that clients can set the X-Forwarded-Prefix header (a misconfigured or absent reverse proxy). Impact is limited to anomalous cookie-path scoping.
- Products
- adminer
- Affected versions
- 4.8.1-1, 4.8.1-2, 4.8.1-4, 5.1.0-1, 5.2.1+dfsg-1, 5.3.0+dfsg-1, 5.4.0+dfsg-1, 5.4.1+dfsg-1, 5.4.2+dfsg-1, 5.4.3+dfsg-1, 5.4.4+dfsg-1, 6.0.0-1, 6.0.1-1, 6.0.2-1, 6.1.0-1, 6.1.1-1, 6.1.2-1
- Fixed versions
- 6.0.0-1
- CVEs
- CVE-2026-16434
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 30 Oct 2026, 09:03 UTC · Revision 1
Source evidence
Adminer 4.6.0 through 5.5.0 (fixed in 5.5.1) contains an incomplete fix for a prior X-Forwarded-Prefix vulnerability (GHSA-8478-xrj3-h9c2). The validation guard (bootstrap.inc.php) only rejects prefixes matching ^/[^/], blocking //evil.com but allowing values such as /\evil.com whose second character is a backslash. Because browsers normalize backslash to forward slash, a network-path reference survives into REQUEST_URI and reaches cookie_path(), affecting the Set-Cookie Path attribute. Exploitation requires that clients can set the X-Forwarded-Prefix header (a misconfigured or absent reverse proxy). Impact is limited to anomalous cookie-path scoping.
osv:DEBIAN-CVE-2026-16434
adminer
Fixed versions: Not specified
adminer
Fixed versions: Not specified
adminer
Fixed versions: 6.0.0-1
Complete source record
{
"id": "748bd382b9b0d2431e4f750aa62ed7a264bb96fa93fc3dffa35c8885d5f892ba",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-16434",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-16434",
"summary": "Adminer 4.6.0 through 5.5.0 (fixed in 5.5.1) contains an incomplete fix for a prior X-Forwarded-Prefix vulnerability (GHSA-8478-xrj3-h9c2). The validation guard (bootstrap.inc.php) only rejects prefixes matching ^/[^/], blocking //evil.com but allowing values such as /\\evil.com whose second character is a backslash. Because browsers normalize backslash to forward slash, a network-path reference survives into REQUEST_URI and reaches cookie_path(), affecting the Set-Cookie Path attribute. Exploitation requires that clients can set the X-Forwarded-Prefix header (a misconfigured or absent reverse proxy). Impact is limited to anomalous cookie-path scoping.",
"evidence": "osv:DEBIAN-CVE-2026-16434",
"products": [
{
"name": {
"value": "adminer",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "4.8.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "4.8.1-2",
"evidence": "/affected/0/versions"
},
{
"value": "4.8.1-4",
"evidence": "/affected/0/versions"
},
{
"value": "5.1.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "5.2.1+dfsg-1",
"evidence": "/affected/0/versions"
},
{
"value": "5.3.0+dfsg-1",
"evidence": "/affected/0/versions"
},
{
"value": "5.4.0+dfsg-1",
"evidence": "/affected/0/versions"
},
{
"value": "5.4.1+dfsg-1",
"evidence": "/affected/0/versions"
},
{
"value": "5.4.2+dfsg-1",
"evidence": "/affected/0/versions"
},
{
"value": "5.4.3+dfsg-1",
"evidence": "/affected/0/versions"
},
{
"value": "5.4.4+dfsg-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.0.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.0.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.0.2-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "6.1.2-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "adminer",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "5.2.1+dfsg-1",
"evidence": "/affected/1/versions"
},
{
"value": "5.3.0+dfsg-1",
"evidence": "/affected/1/versions"
},
{
"value": "5.4.0+dfsg-1",
"evidence": "/affected/1/versions"
},
{
"value": "5.4.1+dfsg-1",
"evidence": "/affected/1/versions"
},
{
"value": "5.4.2+dfsg-1",
"evidence": "/affected/1/versions"
},
{
"value": "5.4.3+dfsg-1",
"evidence": "/affected/1/versions"
},
{
"value": "5.4.4+dfsg-1",
"evidence": "/affected/1/versions"
},
{
"value": "6.0.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "6.0.1-1",
"evidence": "/affected/1/versions"
},
{
"value": "6.0.2-1",
"evidence": "/affected/1/versions"
},
{
"value": "6.1.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "6.1.1-1",
"evidence": "/affected/1/versions"
},
{
"value": "6.1.2-1",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "adminer",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "6.0.0-1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": [
{
"value": "5.2.1+dfsg-1",
"evidence": "/affected/2/versions"
},
{
"value": "5.3.0+dfsg-1",
"evidence": "/affected/2/versions"
},
{
"value": "5.4.0+dfsg-1",
"evidence": "/affected/2/versions"
},
{
"value": "5.4.1+dfsg-1",
"evidence": "/affected/2/versions"
},
{
"value": "5.4.2+dfsg-1",
"evidence": "/affected/2/versions"
},
{
"value": "5.4.3+dfsg-1",
"evidence": "/affected/2/versions"
},
{
"value": "5.4.4+dfsg-1",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "low",
"structured": {
"id": "DEBIAN-CVE-2026-16434",
"aliases": [
"DEBIAN-CVE-2026-16434"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "adminer",
"purl": "pkg:deb/debian/adminer?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"4.8.1-1",
"4.8.1-2",
"4.8.1-4",
"5.1.0-1",
"5.2.1+dfsg-1",
"5.3.0+dfsg-1",
"5.4.0+dfsg-1",
"5.4.1+dfsg-1",
"5.4.2+dfsg-1",
"5.4.3+dfsg-1",
"5.4.4+dfsg-1",
"6.0.0-1",
"6.0.1-1",
"6.0.2-1",
"6.1.0-1",
"6.1.1-1",
"6.1.2-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-16434.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "adminer",
"purl": "pkg:deb/debian/adminer?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"5.2.1+dfsg-1",
"5.3.0+dfsg-1",
"5.4.0+dfsg-1",
"5.4.1+dfsg-1",
"5.4.2+dfsg-1",
"5.4.3+dfsg-1",
"5.4.4+dfsg-1",
"6.0.0-1",
"6.0.1-1",
"6.0.2-1",
"6.1.0-1",
"6.1.1-1",
"6.1.2-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-16434.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "6.0.0-1"
}
]
}
],
"package": {
"name": "adminer",
"purl": "pkg:deb/debian/adminer?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"5.2.1+dfsg-1",
"5.3.0+dfsg-1",
"5.4.0+dfsg-1",
"5.4.1+dfsg-1",
"5.4.2+dfsg-1",
"5.4.3+dfsg-1",
"5.4.4+dfsg-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-16434.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-13T10:00:10.418276705Z",
"provider": "osv",
"upstream": [
"CVE-2026-16434"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-16434"
]
},
"related_cves": [
{
"value": "CVE-2026-16434",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 307599,
"published_at": "2026-08-25T02:16:40.11+00:00"
}