USN-4966-1 (UBUNTU-CVE-2021-31535)

Vulnerability from osv_ubuntu – Published: 2021-05-25 17:00 – Updated: 2026-04-22 07:36 – Source website
VLAI
Summary
libx11 vulnerability
Details

It was discovered that libx11 incorrectly validated certain parameter lengths. A remote attacker could possibly use this issue to trick libx11 into emitting extra X protocol requests.

References
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2021-31535",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:18.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libx11-6",
            "binary_version": "2:1.6.4-3ubuntu0.4"
          },
          {
            "binary_name": "libx11-data",
            "binary_version": "2:1.6.4-3ubuntu0.4"
          },
          {
            "binary_name": "libx11-xcb1",
            "binary_version": "2:1.6.4-3ubuntu0.4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "libx11",
        "purl": "pkg:deb/ubuntu/libx11@2:1.6.4-3ubuntu0.4?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2:1.6.4-3ubuntu0.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2:1.6.4-3",
        "2:1.6.4-3ubuntu0.1",
        "2:1.6.4-3ubuntu0.2",
        "2:1.6.4-3ubuntu0.3"
      ]
    },
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2021-31535",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:20.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libx11-6",
            "binary_version": "2:1.6.9-2ubuntu1.2"
          },
          {
            "binary_name": "libx11-data",
            "binary_version": "2:1.6.9-2ubuntu1.2"
          },
          {
            "binary_name": "libx11-xcb1",
            "binary_version": "2:1.6.9-2ubuntu1.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "libx11",
        "purl": "pkg:deb/ubuntu/libx11@2:1.6.9-2ubuntu1.2?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2:1.6.9-2ubuntu1.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2:1.6.8-1",
        "2:1.6.9-2",
        "2:1.6.9-2ubuntu1",
        "2:1.6.9-2ubuntu1.1"
      ]
    }
  ],
  "aliases": [],
  "details": "It was discovered that libx11 incorrectly validated certain parameter\nlengths. A remote attacker could possibly use this issue to trick libx11\ninto emitting extra X protocol requests.\n",
  "id": "USN-4966-1",
  "modified": "2026-04-22T07:36:59Z",
  "published": "2021-05-25T17:00:37Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-4966-1"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2021-31535"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "summary": "libx11 vulnerability",
  "upstream": [
    "UBUNTU-CVE-2021-31535"
  ]
}



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