HighFix available
libxml2 — security advisory
A flaw was found in libxml2's xmlBuildQName function, where integer overflows in buffer size calculations can lead to a stack-based buffer overflow. This issue can result in memory corruption or a denial of service when processing crafted input.
- Products
- libxml2
- Affected versions
- 2.9.14+dfsg-1.2, 2.9.14+dfsg-1.3~deb12u1, 2.9.14+dfsg-1.3~deb12u2
- Fixed versions
- 2.12.7+dfsg+really2.9.14-2, 2.9.14+dfsg-1.3~deb12u3
- CVEs
- CVE-2025-6021
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 30 Oct 2026, 09:02 UTC · Revision 1
Source evidence
A flaw was found in libxml2's xmlBuildQName function, where integer overflows in buffer size calculations can lead to a stack-based buffer overflow. This issue can result in memory corruption or a denial of service when processing crafted input.
osv:DEBIAN-CVE-2025-6021
libxml2
Fixed versions: 2.9.14+dfsg-1.3~deb12u3
libxml2
Fixed versions: 2.12.7+dfsg+really2.9.14-2
libxml2
Fixed versions: 2.12.7+dfsg+really2.9.14-2
Complete source record
{
"id": "9710e3b4cb3cb4e74cd8a9ade0444e3a8d7e7df53cc4b9d35846c4cf1769407d",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2025-6021",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2025-6021",
"summary": "A flaw was found in libxml2's xmlBuildQName function, where integer overflows in buffer size calculations can lead to a stack-based buffer overflow. This issue can result in memory corruption or a denial of service when processing crafted input.",
"evidence": "osv:DEBIAN-CVE-2025-6021",
"products": [
{
"name": {
"value": "libxml2",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.9.14+dfsg-1.3~deb12u3",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": [
{
"value": "2.9.14+dfsg-1.2",
"evidence": "/affected/0/versions"
},
{
"value": "2.9.14+dfsg-1.3~deb12u1",
"evidence": "/affected/0/versions"
},
{
"value": "2.9.14+dfsg-1.3~deb12u2",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "libxml2",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.12.7+dfsg+really2.9.14-2",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "libxml2",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.12.7+dfsg+really2.9.14-2",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": []
}
],
"severity": "high",
"structured": {
"id": "DEBIAN-CVE-2025-6021",
"aliases": [
"DEBIAN-CVE-2025-6021"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.9.14+dfsg-1.3~deb12u3"
}
]
}
],
"package": {
"name": "libxml2",
"purl": "pkg:deb/debian/libxml2?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"2.9.14+dfsg-1.2",
"2.9.14+dfsg-1.3~deb12u1",
"2.9.14+dfsg-1.3~deb12u2"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2025-6021.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.12.7+dfsg+really2.9.14-2"
}
]
}
],
"package": {
"name": "libxml2",
"purl": "pkg:deb/debian/libxml2?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2025-6021.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.12.7+dfsg+really2.9.14-2"
}
]
}
],
"package": {
"name": "libxml2",
"purl": "pkg:deb/debian/libxml2?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2025-6021.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-13T09:47:25.675274278Z",
"provider": "osv",
"upstream": [
"CVE-2025-6021"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2025-6021"
]
},
"related_cves": [
{
"value": "CVE-2025-6021",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 307551,
"published_at": "2025-06-12T13:15:25.59+00:00"
}