usn-8463-1
Vulnerability from osv_ubuntu
Published
2026-06-23 14:46
Modified
2026-06-23 14:46
Summary
libvncserver vulnerabilities
Details

It was discovered that LibVNCServer had a memory leak in the client cleanup function. An attacker could possibly use this issue to cause LibVNCServer to consume memory, leading to a denial of service. This issue only affected Ubuntu 22.04 LTS. (CVE-2020-29260)

It was discovered that LibVNCServer did not properly validate bounds when handling UltraZip encoding subrectangles. A remote attacker could possibly use this issue to obtain sensitive information or cause a denial of service. This issue only affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 25.04. (CVE-2026-32853)

It was discovered that LibVNCServer did not properly validate return values in the HTTP proxy handlers. A remote attacker could possibly use this issue to cause LibVNCServer to crash, resulting in a denial of service. This issue only affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 25.04. (CVE-2026-32854)

It was discovered that LibVNCServer did not properly handle Tight encoding gradient filter rectangles. A remote attacker could use this issue to cause LibVNCServer to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2026-44988)

References
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2020-29260",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "low",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-32853",
              "severity": [
                {
                  "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N",
                  "type": "CVSS_V4"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-32854",
              "severity": [
                {
                  "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
                  "type": "CVSS_V4"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-44988",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:22.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libvncclient1",
            "binary_version": "0.9.13+dfsg-3ubuntu0.1"
          },
          {
            "binary_name": "libvncserver1",
            "binary_version": "0.9.13+dfsg-3ubuntu0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "libvncserver",
        "purl": "pkg:deb/ubuntu/libvncserver@0.9.13+dfsg-3ubuntu0.1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.9.13+dfsg-3ubuntu0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.9.13+dfsg-3",
        "0.9.13+dfsg-3build1",
        "0.9.13+dfsg-3build2"
      ]
    },
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2026-32853",
              "severity": [
                {
                  "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N",
                  "type": "CVSS_V4"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-32854",
              "severity": [
                {
                  "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
                  "type": "CVSS_V4"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-44988",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:24.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libvncclient1",
            "binary_version": "0.9.14+dfsg-1ubuntu0.1"
          },
          {
            "binary_name": "libvncserver1",
            "binary_version": "0.9.14+dfsg-1ubuntu0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "libvncserver",
        "purl": "pkg:deb/ubuntu/libvncserver@0.9.14+dfsg-1ubuntu0.1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.9.14+dfsg-1ubuntu0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.9.14+dfsg-1",
        "0.9.14+dfsg-1build1",
        "0.9.14+dfsg-1build2"
      ]
    },
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2026-32853",
              "severity": [
                {
                  "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N",
                  "type": "CVSS_V4"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-32854",
              "severity": [
                {
                  "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
                  "type": "CVSS_V4"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-44988",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:25.10"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libvncclient1",
            "binary_version": "0.9.15+dfsg-1ubuntu0.1"
          },
          {
            "binary_name": "libvncserver1",
            "binary_version": "0.9.15+dfsg-1ubuntu0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "libvncserver",
        "purl": "pkg:deb/ubuntu/libvncserver@0.9.15+dfsg-1ubuntu0.1?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.9.15+dfsg-1ubuntu0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.9.14+dfsg-1build2",
        "0.9.15+dfsg-1"
      ]
    },
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2026-44988",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:26.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libvncclient1",
            "binary_version": "0.9.15+dfsg-3ubuntu0.1"
          },
          {
            "binary_name": "libvncserver1",
            "binary_version": "0.9.15+dfsg-3ubuntu0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "libvncserver",
        "purl": "pkg:deb/ubuntu/libvncserver@0.9.15+dfsg-3ubuntu0.1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.9.15+dfsg-3ubuntu0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.9.15+dfsg-1",
        "0.9.15+dfsg-2",
        "0.9.15+dfsg-3"
      ]
    }
  ],
  "aliases": [],
  "details": "It was discovered that LibVNCServer had a memory leak in the client cleanup\nfunction. An attacker could possibly use this issue to cause LibVNCServer\nto consume memory, leading to a denial of service. This issue only affected\nUbuntu 22.04 LTS. (CVE-2020-29260)\n\nIt was discovered that LibVNCServer did not properly validate bounds when\nhandling UltraZip encoding subrectangles. A remote attacker could possibly\nuse this issue to obtain sensitive information or cause a denial of\nservice. This issue only affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and\nUbuntu 25.04. (CVE-2026-32853)\n\nIt was discovered that LibVNCServer did not properly validate return values\nin the HTTP proxy handlers. A remote attacker could possibly use this issue\nto cause LibVNCServer to crash, resulting in a denial of service. This\nissue only affected Ubuntu 22.04 LTS, Ubuntu 24.04 LTS, and Ubuntu 25.04.\n(CVE-2026-32854)\n\nIt was discovered that LibVNCServer did not properly handle Tight encoding\ngradient filter rectangles. A remote attacker could use this issue to cause\nLibVNCServer to crash, resulting in a denial of service, or possibly\nexecute arbitrary code. (CVE-2026-44988)",
  "id": "USN-8463-1",
  "modified": "2026-06-23T14:46:54Z",
  "published": "2026-06-23T14:46:54Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8463-1"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2020-29260"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-32853"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-32854"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-44988"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "summary": "libvncserver vulnerabilities",
  "upstream": [
    "UBUNTU-CVE-2020-29260",
    "UBUNTU-CVE-2026-32853",
    "UBUNTU-CVE-2026-32854",
    "UBUNTU-CVE-2026-44988"
  ]
}



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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

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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.
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  • 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.