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xrdp — security advisory

Type: advisorySources: OSVAdvisory ID: UBUNTU-CVE-2026-55639

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, 0.10.1-3.1, 0.10.1-3.1+deb13u1build0.25.10.1, 0.10.1-4, 0.10.1-4.1, 0.10.1-4.1ubuntu0.1, 0.10.6.1-2ubuntu1, 0.6.0-1, 0.6.0-1ubuntu0.1, 0.6.0-1ubuntu0.1+esm1, 0.6.0-1ubuntu0.1+esm2, 0.6.0-1ubuntu0.1+esm3, 0.6.1-2, 0.6.1-2ubuntu0.1, 0.6.1-2ubuntu0.3, 0.6.1-2ubuntu0.3+esm1, 0.6.1-2ubuntu0.3+esm2, 0.6.1-2ubuntu0.3+esm3, 0.9.1-9, 0.9.12-1, 0.9.12-1ubuntu0.1, 0.9.12-1ubuntu0.1+esm1, 0.9.12-1ubuntu0.1+esm2, 0.9.15-1ubuntu1, 0.9.17-1, 0.9.17-2, 0.9.17-2ubuntu1, 0.9.17-2ubuntu2, 0.9.17-2ubuntu2+esm1, 0.9.17-2ubuntu3, 0.9.17-2ubuntu3+esm1, 0.9.17-2ubuntu3+esm2, 0.9.17-2ubuntu3.1, 0.9.21.1-1, 0.9.24-2, 0.9.24-3, 0.9.24-3build1, 0.9.24-3build2, 0.9.24-4, 0.9.24-4ubuntu0.1, 0.9.24-4ubuntu0.1~esm1, 0.9.4-1, 0.9.4-2, 0.9.4-3, 0.9.4-4, 0.9.4-5, 0.9.5-1, 0.9.5-1build1, 0.9.5-2, 0.9.5-2ubuntu0.1~esm1, 0.9.5-2ubuntu0.1~esm2, 0.9.5-2ubuntu0.1~esm3, 0.9.9-1
Fixed versions
Not specified
CVEs
CVE-2026-55639
Confirmed fixed CVEs
Not specified
Updated in this feed
31 Oct 2026, 02:46 UTC · Revision 1

Source evidence

UBUNTU-CVE-2026-55639

core-osv · Original source

Published 20 Jul 2026, 18:16 UTC

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:UBUNTU-CVE-2026-55639

xrdp

Fixed versions: Not specified

xrdp

Fixed versions: Not specified

xrdp

Fixed versions: Not specified

xrdp

Fixed versions: Not specified

xrdp

Fixed versions: Not specified

xrdp

Fixed versions: Not specified

xrdp

Fixed versions: Not specified

xrdp

Fixed versions: Not specified

xrdp

Fixed versions: Not specified

Complete source record
{
  "id": "e8f248cde5b1746a473f4a0ac911c757538888499f50ef616eec83d212ca762a",
  "url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-55639",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "UBUNTU-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:UBUNTU-CVE-2026-55639",
    "products": [
      {
        "name": {
          "value": "xrdp",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "0.6.0-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "0.6.0-1ubuntu0.1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "0.6.0-1ubuntu0.1+esm1",
            "evidence": "/affected/0/versions"
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          {
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            "evidence": "/affected/0/versions"
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        },
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        "affected_versions": [
          {
            "value": "0.6.1-2",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "0.6.1-2ubuntu0.1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "0.6.1-2ubuntu0.3",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "0.6.1-2ubuntu0.3+esm1",
            "evidence": "/affected/1/versions"
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          },
          {
            "value": "0.9.5-2ubuntu0.1~esm1",
            "evidence": "/affected/2/versions"
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          {
            "value": "0.9.5-2ubuntu0.1~esm2",
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          {
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            "evidence": "/affected/2/versions"
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        ]
      },
      {
        "name": {
          "value": "xrdp",
          "evidence": "/affected/3/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "0.9.9-1",
            "evidence": "/affected/3/versions"
          },
          {
            "value": "0.9.12-1",
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          {
            "value": "0.9.12-1ubuntu0.1",
            "evidence": "/affected/3/versions"
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      {
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        "affected_versions": [
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            "evidence": "/affected/4/versions"
          },
          {
            "value": "0.9.17-1",
            "evidence": "/affected/4/versions"
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            "evidence": "/affected/4/versions"
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          {
            "value": "0.9.17-2ubuntu3",
            "evidence": "/affected/4/versions"
          },
          {
            "value": "0.9.17-2ubuntu3+esm1",
            "evidence": "/affected/4/versions"
          },
          {
            "value": "0.9.17-2ubuntu3+esm2",
            "evidence": "/affected/4/versions"
          },
          {
            "value": "0.9.17-2ubuntu3.1",
            "evidence": "/affected/4/versions"
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        ]
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      {
        "name": {
          "value": "xrdp",
          "evidence": "/affected/5/package/name"
        },
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          {
            "value": "0.9.21.1-1",
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          },
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            "evidence": "/affected/5/versions"
          },
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            "evidence": "/affected/5/versions"
          },
          {
            "value": "0.9.24-3build1",
            "evidence": "/affected/5/versions"
          },
          {
            "value": "0.9.24-3build2",
            "evidence": "/affected/5/versions"
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          {
            "value": "0.9.24-4",
            "evidence": "/affected/5/versions"
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            "value": "0.9.24-4ubuntu0.1~esm1",
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            "evidence": "/affected/5/versions"
          }
        ]
      },
      {
        "name": {
          "value": "xrdp",
          "evidence": "/affected/6/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "0.10.1-3",
            "evidence": "/affected/6/versions"
          },
          {
            "value": "0.10.1-3.1",
            "evidence": "/affected/6/versions"
          },
          {
            "value": "0.10.1-3.1+deb13u1build0.25.10.1",
            "evidence": "/affected/6/versions"
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        ]
      },
      {
        "name": {
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          "evidence": "/affected/7/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "0.10.1-4.1",
            "evidence": "/affected/7/versions"
          },
          {
            "value": "0.10.6.1-2ubuntu1",
            "evidence": "/affected/7/versions"
          }
        ]
      },
      {
        "name": {
          "value": "xrdp",
          "evidence": "/affected/8/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "0.10.1-3.1",
            "evidence": "/affected/8/versions"
          },
          {
            "value": "0.10.1-4",
            "evidence": "/affected/8/versions"
          },
          {
            "value": "0.10.1-4.1",
            "evidence": "/affected/8/versions"
          },
          {
            "value": "0.10.1-4.1ubuntu0.1",
            "evidence": "/affected/8/versions"
          }
        ]
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "UBUNTU-CVE-2026-55639",
      "aliases": [
        "UBUNTU-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"
        },
        {
          "type": "Ubuntu",
          "score": "medium"
        }
      ],
      "affected": [
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              "events": [
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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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            "name": "xrdp",
            "purl": "pkg:deb/ubuntu/xrdp?arch=source&distro=questing",
            "ecosystem": "Ubuntu:25.10"
          },
          "versions": [
            "0.10.1-3",
            "0.10.1-3.1",
            "0.10.1-3.1+deb13u1build0.25.10.1"
          ],
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          },
          "ecosystem_specific": {
            "binaries": [
              {
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                "binary_version": "0.10.1-3.1+deb13u1build0.25.10.1"
              }
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        },
        {
          "ranges": [
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          ],
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            "purl": "pkg:deb/ubuntu/xrdp?arch=source&distro=stonking",
            "ecosystem": "Ubuntu:26.10"
          },
          "versions": [
            "0.10.1-4.1",
            "0.10.6.1-2ubuntu1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55639.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "xrdp",
                "binary_version": "0.10.6.1-2ubuntu1"
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
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          ],
          "package": {
            "name": "xrdp",
            "purl": "pkg:deb/ubuntu/xrdp?arch=source&distro=resolute",
            "ecosystem": "Ubuntu:26.04:LTS"
          },
          "versions": [
            "0.10.1-3.1",
            "0.10.1-4",
            "0.10.1-4.1",
            "0.10.1-4.1ubuntu0.1"
          ],
          "database_specific": {
            "source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-55639.json"
          },
          "ecosystem_specific": {
            "binaries": [
              {
                "binary_name": "xrdp",
                "binary_version": "0.10.1-4.1ubuntu0.1"
              }
            ]
          }
        }
      ],
      "modified": "2026-10-17T12:59:08.491566615Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-55639"
      ],
      "references": [
        "https://ubuntu.com/security/CVE-2026-55639",
        "https://www.cve.org/CVERecord?id=CVE-2026-55639",
        "https://github.com/neutrinolabs/xrdp/security/advisories/GHSA-6g36-mxcf-r3gc"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-55639",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 359337,
  "published_at": "2026-07-20T18:16:00+00:00"
}