HighFix available
xorg-server, xwayland — security advisory
A flaw was found in the X.Org X server. This use-after-free vulnerability occurs in the XSYNC fence triggering logic, specifically within the miSyncTriggerFence() function. An attacker with access to the X11 server can exploit this without user interaction, leading to a server crash and potentially enabling memory corruption. This could result in a denial of service or further compromise of the system.
- Products
- xorg-server, xwayland
- Affected versions
- 2:21.1.16-1.3, 2:21.1.16-1.3+deb13u1, 2:21.1.18-1, 2:21.1.18-2, 2:21.1.20-1, 2:21.1.21-1, 2:21.1.7-3, 2:21.1.7-3+deb12u1, 2:21.1.7-3+deb12u10, 2:21.1.7-3+deb12u11, 2:21.1.7-3+deb12u2, 2:21.1.7-3+deb12u3, 2:21.1.7-3+deb12u4, 2:21.1.7-3+deb12u5, 2:21.1.7-3+deb12u6, 2:21.1.7-3+deb12u7, 2:21.1.7-3+deb12u8, 2:21.1.7-3+deb12u9, 2:22.1.9-1, 2:23.1.0-1, 2:23.1.1-1, 2:23.2.0-1, 2:23.2.1-1, 2:23.2.2-1, 2:23.2.3-1, 2:23.2.4-1, 2:23.2.6-1, 2:24.0.99.901-1, 2:24.1.0-1, 2:24.1.10-1, 2:24.1.11-1, 2:24.1.12-1, 2:24.1.13-1, 2:24.1.14-1, 2:24.1.2-1, 2:24.1.3-1, 2:24.1.4-1, 2:24.1.4-2, 2:24.1.4-3, 2:24.1.5-1, 2:24.1.6-1, 2:24.1.8-1, 2:24.1.9-1
- Fixed versions
- 2:21.1.16-1.3+deb13u2, 2:21.1.22-1, 2:21.1.7-3+deb12u12, 2:24.1.10-1
- CVEs
- CVE-2026-34001
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 17:52 UTC · Revision 2
Source evidence
A flaw was found in the X.Org X server. This use-after-free vulnerability occurs in the XSYNC fence triggering logic, specifically within the miSyncTriggerFence() function. An attacker with access to the X11 server can exploit this without user interaction, leading to a server crash and potentially enabling memory corruption. This could result in a denial of service or further compromise of the system.
osv:DEBIAN-CVE-2026-34001
xorg-server
Fixed versions: 2:21.1.7-3+deb12u12
xorg-server
Fixed versions: 2:21.1.16-1.3+deb13u2
xorg-server
Fixed versions: 2:21.1.22-1
xwayland
Fixed versions: Not specified
xwayland
Fixed versions: Not specified
xwayland
Fixed versions: 2:24.1.10-1
Complete source record
{
"id": "acc71df16786affb7feb1b8f73b0790b96ba908ccb01f0f9a5673f5fcc52da63",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-34001",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-34001",
"summary": "A flaw was found in the X.Org X server. This use-after-free vulnerability occurs in the XSYNC fence triggering logic, specifically within the miSyncTriggerFence() function. An attacker with access to the X11 server can exploit this without user interaction, leading to a server crash and potentially enabling memory corruption. This could result in a denial of service or further compromise of the system.",
"evidence": "osv:DEBIAN-CVE-2026-34001",
"products": [
{
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{
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"evidence": "/affected/0/versions"
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{
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"evidence": "/affected/0/versions"
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{
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{
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{
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{
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{
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{
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{
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{
"value": "2:23.2.3-1",
"evidence": "/affected/3/versions"
},
{
"value": "2:23.2.4-1",
"evidence": "/affected/3/versions"
},
{
"value": "2:23.2.6-1",
"evidence": "/affected/3/versions"
},
{
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"evidence": "/affected/3/versions"
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{
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"evidence": "/affected/3/versions"
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{
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{
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},
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{
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{
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{
"name": {
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},
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"evidence": "/affected/4/versions"
},
{
"value": "2:24.1.11-1",
"evidence": "/affected/4/versions"
},
{
"value": "2:24.1.12-1",
"evidence": "/affected/4/versions"
},
{
"value": "2:24.1.13-1",
"evidence": "/affected/4/versions"
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{
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"evidence": "/affected/4/versions"
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{
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{
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"evidence": "/affected/5/versions"
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{
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{
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],
"severity": "high",
"structured": {
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"aliases": [
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],
"metrics": [
{
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"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
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],
"affected": [
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],
"package": {
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"purl": "pkg:deb/debian/xorg-server?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
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"2:21.1.7-3+deb12u10",
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"2:21.1.7-3+deb12u2",
"2:21.1.7-3+deb12u3",
"2:21.1.7-3+deb12u4",
"2:21.1.7-3+deb12u5",
"2:21.1.7-3+deb12u6",
"2:21.1.7-3+deb12u7",
"2:21.1.7-3+deb12u8",
"2:21.1.7-3+deb12u9"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-34001.json"
},
"ecosystem_specific": {
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}
},
{
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],
"package": {
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},
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},
{
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],
"package": {
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},
"versions": [
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],
"database_specific": {
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},
"ecosystem_specific": {
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}
}
],
"modified": "2026-10-27T10:00:59.714279885Z",
"provider": "osv",
"upstream": [
"CVE-2026-34001"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-34001"
]
},
"related_cves": [
{
"value": "CVE-2026-34001",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 461411,
"published_at": "2026-04-23T16:16:24.777+00:00"
}