qemu — security advisory
A flaw was found in the QEMU built-in VNC server. When a client connects to the VNC server, QEMU checks whether the current number of connections crosses a certain threshold and if so, cleans up the previous connection. If the previous connection happens to be in the handshake phase and fails, QEMU cleans up the connection again, resulting in a NULL pointer dereference issue. This could allow a remote unauthenticated client to cause a denial of service.
- Products
- qemu
- Affected versions
- 1:7.2+dfsg-7, 1:7.2+dfsg-7+deb12u1, 1:7.2+dfsg-7+deb12u2~bpo11+1
- Fixed versions
- 1:7.2+dfsg-7+deb12u2, 1:8.0.4+dfsg-1
- CVEs
- CVE-2023-3354
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 15:52 UTC · Revision 1
Source evidence
A flaw was found in the QEMU built-in VNC server. When a client connects to the VNC server, QEMU checks whether the current number of connections crosses a certain threshold and if so, cleans up the previous connection. If the previous connection happens to be in the handshake phase and fails, QEMU cleans up the connection again, resulting in a NULL pointer dereference issue. This could allow a remote unauthenticated client to cause a denial of service.
osv:DEBIAN-CVE-2023-3354
qemu
Fixed versions: 1:7.2+dfsg-7+deb12u2
qemu
Fixed versions: 1:8.0.4+dfsg-1
qemu
Fixed versions: 1:8.0.4+dfsg-1
Complete source record
{
"id": "8ee91adcb293cf98264e5b30adc1f50f2bf27a6ef3df939a4dec42798fc0c93d",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2023-3354",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2023-3354",
"summary": "A flaw was found in the QEMU built-in VNC server. When a client connects to the VNC server, QEMU checks whether the current number of connections crosses a certain threshold and if so, cleans up the previous connection. If the previous connection happens to be in the handshake phase and fails, QEMU cleans up the connection again, resulting in a NULL pointer dereference issue. This could allow a remote unauthenticated client to cause a denial of service.",
"evidence": "osv:DEBIAN-CVE-2023-3354",
"products": [
{
"name": {
"value": "qemu",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:7.2+dfsg-7+deb12u2",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": [
{
"value": "1:7.2+dfsg-7",
"evidence": "/affected/0/versions"
},
{
"value": "1:7.2+dfsg-7+deb12u1",
"evidence": "/affected/0/versions"
},
{
"value": "1:7.2+dfsg-7+deb12u2~bpo11+1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "qemu",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:8.0.4+dfsg-1",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "qemu",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:8.0.4+dfsg-1",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": []
}
],
"severity": "high",
"structured": {
"id": "DEBIAN-CVE-2023-3354",
"aliases": [
"DEBIAN-CVE-2023-3354"
],
"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": "1:7.2+dfsg-7+deb12u2"
}
]
}
],
"package": {
"name": "qemu",
"purl": "pkg:deb/debian/qemu?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"1:7.2+dfsg-7",
"1:7.2+dfsg-7+deb12u1",
"1:7.2+dfsg-7+deb12u2~bpo11+1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-3354.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:8.0.4+dfsg-1"
}
]
}
],
"package": {
"name": "qemu",
"purl": "pkg:deb/debian/qemu?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-3354.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:8.0.4+dfsg-1"
}
]
}
],
"package": {
"name": "qemu",
"purl": "pkg:deb/debian/qemu?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-3354.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-26T18:02:16.832961851Z",
"provider": "osv",
"upstream": [
"CVE-2023-3354"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2023-3354"
]
},
"related_cves": [
{
"value": "CVE-2023-3354",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 455933,
"published_at": "2023-07-11T17:15:13.387+00:00"
}