MediumFix available
qemu — security advisory
A flaw was found in the QEMU built-in VNC server while processing ClientCutText messages. The qemu_clipboard_request() function can be reached before vnc_server_cut_text_caps() was called and had the chance to initialize the clipboard peer, leading to a NULL pointer dereference. This could allow a malicious authenticated VNC client to crash QEMU and trigger 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, 1:7.2+dfsg-7+deb12u2~bpo11+1, 1:7.2+dfsg-7+deb12u3
- Fixed versions
- 1:7.2+dfsg-7+deb12u4, 1:8.2.0+ds-5
- CVEs
- CVE-2023-6683
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 16:31 UTC · Revision 1
Source evidence
A flaw was found in the QEMU built-in VNC server while processing ClientCutText messages. The qemu_clipboard_request() function can be reached before vnc_server_cut_text_caps() was called and had the chance to initialize the clipboard peer, leading to a NULL pointer dereference. This could allow a malicious authenticated VNC client to crash QEMU and trigger a denial of service.
osv:DEBIAN-CVE-2023-6683
qemu
Fixed versions: 1:7.2+dfsg-7+deb12u4
qemu
Fixed versions: 1:8.2.0+ds-5
qemu
Fixed versions: 1:8.2.0+ds-5
Complete source record
{
"id": "df5ddc81872244f2891d5cbe892c491c6c67c67ea08b8855d05e67d23a45c8f4",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2023-6683",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2023-6683",
"summary": "A flaw was found in the QEMU built-in VNC server while processing ClientCutText messages. The qemu_clipboard_request() function can be reached before vnc_server_cut_text_caps() was called and had the chance to initialize the clipboard peer, leading to a NULL pointer dereference. This could allow a malicious authenticated VNC client to crash QEMU and trigger a denial of service.",
"evidence": "osv:DEBIAN-CVE-2023-6683",
"products": [
{
"name": {
"value": "qemu",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:7.2+dfsg-7+deb12u4",
"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",
"evidence": "/affected/0/versions"
},
{
"value": "1:7.2+dfsg-7+deb12u2~bpo11+1",
"evidence": "/affected/0/versions"
},
{
"value": "1:7.2+dfsg-7+deb12u3",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "qemu",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:8.2.0+ds-5",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": []
},
{
"name": {
"value": "qemu",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "1:8.2.0+ds-5",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": []
}
],
"severity": "medium",
"structured": {
"id": "DEBIAN-CVE-2023-6683",
"aliases": [
"DEBIAN-CVE-2023-6683"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:7.2+dfsg-7+deb12u4"
}
]
}
],
"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",
"1:7.2+dfsg-7+deb12u2~bpo11+1",
"1:7.2+dfsg-7+deb12u3"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-6683.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:8.2.0+ds-5"
}
]
}
],
"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-2023-6683.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1:8.2.0+ds-5"
}
]
}
],
"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-2023-6683.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-26T18:03:10.374687338Z",
"provider": "osv",
"upstream": [
"CVE-2023-6683"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2023-6683"
]
},
"related_cves": [
{
"value": "CVE-2023-6683",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 457981,
"published_at": "2024-01-12T19:15:11.48+00:00"
}