CVE-2026-55639 (GCVE-0-2026-55639)

Vulnerability from cvelistv5 – Published: 2026-07-20 17:14 – Updated: 2026-07-20 19:06
VLAI
Title
xrdp: Out-of-bounds read in GCC Conference Create Request CS_SECURITY processing (xrdp_sec_process_mcs_data_CS_SECURITY)
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.
Severity
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
Assigner
References
Impacted products
Vendor Product Version
neutrinolabs xrdp Affected: < 0.10.6.1
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-55639",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-20T19:01:32.890448Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-20T19:06:59.250Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "xrdp",
          "vendor": "neutrinolabs",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.10.6.1"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-125",
              "description": "CWE-125: Out-of-bounds Read",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-20T17:14:50.233Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/neutrinolabs/xrdp/security/advisories/GHSA-6g36-mxcf-r3gc",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/neutrinolabs/xrdp/security/advisories/GHSA-6g36-mxcf-r3gc"
        },
        {
          "name": "https://github.com/neutrinolabs/xrdp/releases/tag/v0.10.6.1",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/neutrinolabs/xrdp/releases/tag/v0.10.6.1"
        }
      ],
      "source": {
        "advisory": "GHSA-6g36-mxcf-r3gc",
        "discovery": "UNKNOWN"
      },
      "title": "xrdp: Out-of-bounds read in GCC Conference Create Request CS_SECURITY processing (xrdp_sec_process_mcs_data_CS_SECURITY)"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-55639",
    "datePublished": "2026-07-20T17:14:50.233Z",
    "dateReserved": "2026-06-16T23:52:12.057Z",
    "dateUpdated": "2026-07-20T19:06:59.250Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-55639",
      "date": "2026-07-22",
      "epss": "0.00424",
      "percentile": "0.3469"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-55639\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-07-20T18:16:54.287\",\"lastModified\":\"2026-07-21T19:49:44.020\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"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.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"neutrinolabs\",\"product\":\"xrdp\",\"versions\":[{\"version\":\"\u003c 0.10.6.1\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N\",\"baseScore\":5.3,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"LOW\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":3.9,\"impactScore\":1.4}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-07-20T19:01:32.890448Z\",\"id\":\"CVE-2026-55639\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"yes\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-125\"}]}],\"references\":[{\"url\":\"https://github.com/neutrinolabs/xrdp/releases/tag/v0.10.6.1\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/neutrinolabs/xrdp/security/advisories/GHSA-6g36-mxcf-r3gc\",\"source\":\"security-advisories@github.com\"}]}}",
    "redhat_vex": {
      "current_release_date": "2026-07-21T20:54:29+00:00",
      "cve": "CVE-2026-55639",
      "id": "CVE-2026-55639",
      "initial_release_date": "2026-07-20T17:14:50.233000+00:00",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "xrdp: improper input validation in MCS data processing leads to potential information leak",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-55639.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-07-21T13:06:19Z",
      "cve": "CVE-2026-55639",
      "id": "CVE-2026-55639",
      "initial_release_date": "2026-07-21T13:06:19Z",
      "product_status:known_affected": "93",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-55639",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-55639.json",
      "version": "2"
    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-55639\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-07-20T19:01:32.890448Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-07-20T19:01:33.715Z\"}}], \"cna\": {\"title\": \"xrdp: Out-of-bounds read in GCC Conference Create Request CS_SECURITY processing (xrdp_sec_process_mcs_data_CS_SECURITY)\", \"source\": {\"advisory\": \"GHSA-6g36-mxcf-r3gc\", \"discovery\": \"UNKNOWN\"}, \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 5.3, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"NONE\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"LOW\"}}], \"affected\": [{\"vendor\": \"neutrinolabs\", \"product\": \"xrdp\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003c 0.10.6.1\"}]}], \"references\": [{\"url\": \"https://github.com/neutrinolabs/xrdp/security/advisories/GHSA-6g36-mxcf-r3gc\", \"name\": \"https://github.com/neutrinolabs/xrdp/security/advisories/GHSA-6g36-mxcf-r3gc\", \"tags\": [\"x_refsource_CONFIRM\"]}, {\"url\": \"https://github.com/neutrinolabs/xrdp/releases/tag/v0.10.6.1\", \"name\": \"https://github.com/neutrinolabs/xrdp/releases/tag/v0.10.6.1\", \"tags\": [\"x_refsource_MISC\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"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.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-125\", \"description\": \"CWE-125: Out-of-bounds Read\"}]}], \"providerMetadata\": {\"orgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"shortName\": \"GitHub_M\", \"dateUpdated\": \"2026-07-20T17:14:50.233Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-55639\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-07-20T19:06:59.250Z\", \"dateReserved\": \"2026-06-16T23:52:12.057Z\", \"assignerOrgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"datePublished\": \"2026-07-20T17:14:50.233Z\", \"assignerShortName\": \"GitHub_M\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.