ubuntu-cve-2026-34743
Vulnerability from osv_ubuntu
Published
2026-04-02 19:21
Modified
2026-06-02 13:28
Summary
Details

XZ Utils provide a general-purpose data-compression library plus command-line tools. Prior to version 5.8.3, if lzma_index_decoder() was used to decode an Index that contained no Records, the resulting lzma_index was left in a state where where a subsequent lzma_index_append() would allocate too little memory, and a buffer overflow would occur. This issue has been patched in version 5.8.3.

Severity
1.7 (Low)
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/E:U
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
N/A (UNKNOWN)
low
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "liblzma5",
            "binary_version": "5.1.1alpha+20120614-2ubuntu2.14.04.1+esm2"
          },
          {
            "binary_name": "xz-utils",
            "binary_version": "5.1.1alpha+20120614-2ubuntu2.14.04.1+esm2"
          },
          {
            "binary_name": "xzdec",
            "binary_version": "5.1.1alpha+20120614-2ubuntu2.14.04.1+esm2"
          }
        ],
        "priority_reason": "Issue not likely to affect any real-world applications"
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:14.04:LTS",
        "name": "xz-utils",
        "purl": "pkg:deb/ubuntu/xz-utils@5.1.1alpha+20120614-2ubuntu2.14.04.1+esm2?arch=source\u0026distro=esm-infra-legacy/trusty"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5.1.1alpha+20120614-2ubuntu2.14.04.1+esm2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "5.1.1alpha+20120614-2ubuntu1",
        "5.1.1alpha+20120614-2ubuntu2",
        "5.1.1alpha+20120614-2ubuntu2.14.04.1+esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "liblzma5",
            "binary_version": "5.1.1alpha+20120614-2ubuntu2.16.04.1+esm2"
          },
          {
            "binary_name": "xz-utils",
            "binary_version": "5.1.1alpha+20120614-2ubuntu2.16.04.1+esm2"
          },
          {
            "binary_name": "xzdec",
            "binary_version": "5.1.1alpha+20120614-2ubuntu2.16.04.1+esm2"
          }
        ],
        "priority_reason": "Issue not likely to affect any real-world applications"
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "xz-utils",
        "purl": "pkg:deb/ubuntu/xz-utils@5.1.1alpha+20120614-2ubuntu2.16.04.1+esm2?arch=source\u0026distro=esm-infra-legacy/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5.1.1alpha+20120614-2ubuntu2.16.04.1+esm2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "5.1.1alpha+20120614-2ubuntu2",
        "5.1.1alpha+20120614-2ubuntu2.16.04.1+esm1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "liblzma5",
            "binary_version": "5.2.2-1.3ubuntu0.1+esm1"
          },
          {
            "binary_name": "xz-utils",
            "binary_version": "5.2.2-1.3ubuntu0.1+esm1"
          },
          {
            "binary_name": "xzdec",
            "binary_version": "5.2.2-1.3ubuntu0.1+esm1"
          }
        ],
        "priority_reason": "Issue not likely to affect any real-world applications"
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "xz-utils",
        "purl": "pkg:deb/ubuntu/xz-utils@5.2.2-1.3ubuntu0.1+esm1?arch=source\u0026distro=esm-infra/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5.2.2-1.3ubuntu0.1+esm1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "5.2.2-1.3",
        "5.2.2-1.3ubuntu0.1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "liblzma5",
            "binary_version": "5.2.4-1ubuntu1.1+esm1"
          },
          {
            "binary_name": "xz-utils",
            "binary_version": "5.2.4-1ubuntu1.1+esm1"
          },
          {
            "binary_name": "xzdec",
            "binary_version": "5.2.4-1ubuntu1.1+esm1"
          }
        ],
        "priority_reason": "Issue not likely to affect any real-world applications"
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "xz-utils",
        "purl": "pkg:deb/ubuntu/xz-utils@5.2.4-1ubuntu1.1+esm1?arch=source\u0026distro=esm-infra/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5.2.4-1ubuntu1.1+esm1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "5.2.4-1",
        "5.2.4-1ubuntu1",
        "5.2.4-1ubuntu1.1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "liblzma5",
            "binary_version": "5.2.5-2ubuntu1.1"
          },
          {
            "binary_name": "xz-utils",
            "binary_version": "5.2.5-2ubuntu1.1"
          },
          {
            "binary_name": "xzdec",
            "binary_version": "5.2.5-2ubuntu1.1"
          }
        ],
        "priority_reason": "Issue not likely to affect any real-world applications"
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "xz-utils",
        "purl": "pkg:deb/ubuntu/xz-utils@5.2.5-2ubuntu1.1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5.2.5-2ubuntu1.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "5.2.5-2",
        "5.2.5-2build1",
        "5.2.5-2build2",
        "5.2.5-2ubuntu1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "liblzma5",
            "binary_version": "5.6.1+really5.4.5-1ubuntu0.3"
          },
          {
            "binary_name": "xz-utils",
            "binary_version": "5.6.1+really5.4.5-1ubuntu0.3"
          },
          {
            "binary_name": "xzdec",
            "binary_version": "5.6.1+really5.4.5-1ubuntu0.3"
          }
        ],
        "priority_reason": "Issue not likely to affect any real-world applications"
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "xz-utils",
        "purl": "pkg:deb/ubuntu/xz-utils@5.6.1+really5.4.5-1ubuntu0.3?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5.6.1+really5.4.5-1ubuntu0.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "5.4.1-0.2",
        "5.4.4-0.1",
        "5.4.5-0.1",
        "5.4.5-0.3",
        "5.6.0-0.2",
        "5.6.1+really5.4.5-1",
        "5.6.1+really5.4.5-1build0.1",
        "5.6.1+really5.4.5-1ubuntu0.2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "liblzma5",
            "binary_version": "5.8.1-1ubuntu0.1"
          },
          {
            "binary_name": "xz-utils",
            "binary_version": "5.8.1-1ubuntu0.1"
          },
          {
            "binary_name": "xzdec",
            "binary_version": "5.8.1-1ubuntu0.1"
          }
        ],
        "priority_reason": "Issue not likely to affect any real-world applications"
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "xz-utils",
        "purl": "pkg:deb/ubuntu/xz-utils@5.8.1-1ubuntu0.1?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5.8.1-1ubuntu0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "5.6.4-1ubuntu1",
        "5.8.1-1",
        "5.8.1-1build1",
        "5.8.1-1build2"
      ]
    }
  ],
  "aliases": [],
  "details": "XZ Utils provide a general-purpose data-compression library plus command-line tools. Prior to version 5.8.3, if lzma_index_decoder() was used to decode an Index that contained no Records, the resulting lzma_index was left in a state where where a subsequent lzma_index_append() would allocate too little memory, and a buffer overflow would occur. This issue has been patched in version 5.8.3.",
  "id": "UBUNTU-CVE-2026-34743",
  "modified": "2026-06-02T13:28:07Z",
  "published": "2026-04-02T19:21:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-34743"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-34743"
    },
    {
      "type": "REPORT",
      "url": "https://tukaani.org/xz/index-append-overflow.html"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8362-1"
    }
  ],
  "related": [
    "USN-8362-1"
  ],
  "schema_version": "1.7.0",
  "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/E:U",
      "type": "CVSS_V4"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    },
    {
      "score": "low",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-34743"
  ]
}



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