xrdp — security advisory
xrdp is an open source RDP server. Versions 0.10.6 and prior contain a vulnerability concerning the parsing of Client Security Data within the Client MCS Connect Initial PDU with GCC Conference Create Request during the connection sequence. During the initial capability and security negotiation phase, the parser fails to perform sufficient length validation for the incoming data block. A remote, unauthenticated attacker could potentially exploit this flaw by sending a specially crafted RDP packet containing malformed data. Due to missing bounds checks, the xrdp process may read a small number of bytes beyond the declared data block boundary, potentially disclosing process memory contents that could be combined with other vulnerabilities. This issue has been fixed in version 0.10.6.1.
- Products
- xrdp
- Affected versions
- 0.10.1-3.1, 0.10.1-3.1+deb13u1, 0.10.1-4, 0.10.1-4.1, 0.10.2-1, 0.10.2-2, 0.10.4.1-1, 0.10.4.1-2, 0.10.5-1, 0.10.5-2, 0.10.5-3, 0.10.5-4, 0.10.5-5, 0.10.6-1, 0.10.6-2, 0.10.6-3, 0.10.6-4, 0.10.6-5, 0.10.6.1-1, 0.10.6.1-2~bpo13+1, 0.9.21.1-1, 0.9.21.1-1+deb12u1, 0.9.21.1-1+deb12u2
- Fixed versions
- 0.10.1-3.1+deb13u2, 0.10.6.1-2, 0.9.21.1-1+deb12u3
- CVEs
- CVE-2026-55639
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 09:52 UTC · Revision 2
Source evidence
xrdp is an open source RDP server. Versions 0.10.6 and prior contain a vulnerability concerning the parsing of Client Security Data within the Client MCS Connect Initial PDU with GCC Conference Create Request during the connection sequence. During the initial capability and security negotiation phase, the parser fails to perform sufficient length validation for the incoming data block. A remote, unauthenticated attacker could potentially exploit this flaw by sending a specially crafted RDP packet containing malformed data. Due to missing bounds checks, the xrdp process may read a small number of bytes beyond the declared data block boundary, potentially disclosing process memory contents that could be combined with other vulnerabilities. This issue has been fixed in version 0.10.6.1.
osv:DEBIAN-CVE-2026-55639
xrdp
Fixed versions: 0.9.21.1-1+deb12u3
xrdp
Fixed versions: 0.10.1-3.1+deb13u2
xrdp
Fixed versions: 0.10.6.1-2
Complete source record
{
"id": "551c319160e5196e381b79eb3479411e618bdcbb94067a1a52b94f9adf876a45",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-55639",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-55639",
"summary": "xrdp is an open source RDP server. Versions 0.10.6 and prior contain a vulnerability concerning the parsing of Client Security Data within the Client MCS Connect Initial PDU with GCC Conference Create Request during the connection sequence. During the initial capability and security negotiation phase, the parser fails to perform sufficient length validation for the incoming data block. A remote, unauthenticated attacker could potentially exploit this flaw by sending a specially crafted RDP packet containing malformed data. Due to missing bounds checks, the xrdp process may read a small number of bytes beyond the declared data block boundary, potentially disclosing process memory contents that could be combined with other vulnerabilities. This issue has been fixed in version 0.10.6.1.",
"evidence": "osv:DEBIAN-CVE-2026-55639",
"products": [
{
"name": {
"value": "xrdp",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "0.9.21.1-1+deb12u3",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": [
{
"value": "0.9.21.1-1",
"evidence": "/affected/0/versions"
},
{
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"evidence": "/affected/0/versions"
},
{
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"evidence": "/affected/0/versions"
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{
"name": {
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"evidence": "/affected/1/package/name"
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"evidence": "/affected/1/ranges"
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"affected_versions": [
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"evidence": "/affected/1/versions"
},
{
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"evidence": "/affected/1/versions"
}
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},
{
"name": {
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},
"prerequisites": [],
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"evidence": "/affected/2/ranges"
}
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"affected_versions": [
{
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"evidence": "/affected/2/versions"
},
{
"value": "0.10.1-4",
"evidence": "/affected/2/versions"
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{
"value": "0.10.1-4.1",
"evidence": "/affected/2/versions"
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{
"value": "0.10.2-1",
"evidence": "/affected/2/versions"
},
{
"value": "0.10.2-2",
"evidence": "/affected/2/versions"
},
{
"value": "0.10.4.1-1",
"evidence": "/affected/2/versions"
},
{
"value": "0.10.4.1-2",
"evidence": "/affected/2/versions"
},
{
"value": "0.10.5-1",
"evidence": "/affected/2/versions"
},
{
"value": "0.10.5-2",
"evidence": "/affected/2/versions"
},
{
"value": "0.10.5-3",
"evidence": "/affected/2/versions"
},
{
"value": "0.10.5-4",
"evidence": "/affected/2/versions"
},
{
"value": "0.10.5-5",
"evidence": "/affected/2/versions"
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{
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"evidence": "/affected/2/versions"
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{
"value": "0.10.6-2",
"evidence": "/affected/2/versions"
},
{
"value": "0.10.6-3",
"evidence": "/affected/2/versions"
},
{
"value": "0.10.6-4",
"evidence": "/affected/2/versions"
},
{
"value": "0.10.6-5",
"evidence": "/affected/2/versions"
},
{
"value": "0.10.6.1-1",
"evidence": "/affected/2/versions"
},
{
"value": "0.10.6.1-2~bpo13+1",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "medium",
"structured": {
"id": "DEBIAN-CVE-2026-55639",
"aliases": [
"DEBIAN-CVE-2026-55639"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
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}
]
}
],
"package": {
"name": "xrdp",
"purl": "pkg:deb/debian/xrdp?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
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"0.9.21.1-1+deb12u1",
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],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-55639.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "0.10.1-3.1+deb13u2"
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]
}
],
"package": {
"name": "xrdp",
"purl": "pkg:deb/debian/xrdp?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
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"0.10.1-3.1+deb13u1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-55639.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
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},
{
"fixed": "0.10.6.1-2"
}
]
}
],
"package": {
"name": "xrdp",
"purl": "pkg:deb/debian/xrdp?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"0.10.1-3.1",
"0.10.1-4",
"0.10.1-4.1",
"0.10.2-1",
"0.10.2-2",
"0.10.4.1-1",
"0.10.4.1-2",
"0.10.5-1",
"0.10.5-2",
"0.10.5-3",
"0.10.5-4",
"0.10.5-5",
"0.10.6-1",
"0.10.6-2",
"0.10.6-3",
"0.10.6-4",
"0.10.6-5",
"0.10.6.1-1",
"0.10.6.1-2~bpo13+1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-55639.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-25T09:47:40.623652191Z",
"provider": "osv",
"upstream": [
"CVE-2026-55639"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-55639"
]
},
"related_cves": [
{
"value": "CVE-2026-55639",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 445155,
"published_at": "2026-07-20T18:16:54.287+00:00"
}