ubuntu-cve-2026-56391
Vulnerability from osv_ubuntu
Published
2026-07-24 09:16
Modified
2026-07-29 07:59
Summary
Details

GNU coreutils uniq is vulnerable to an out‑of‑bounds read due to incorrect handling of multibyte input when the -w (--check-chars) option is used. The find_field() function miscalculates the byte length of characters by repeatedly processing a fixed pointer instead of advancing through the input, resulting in an inflated length value. This incorrect length is later used in a memcmp operation, causing reads beyond the allocated buffer when processing crafted multibyte input. When running GNU coreutils uniq with attacker-provided arguments, this behavior leads to a crash and potential adjacent heap memory exposure. This issue has been fixed in the commit d64e35a8a4c0e4608321433e0d84d917e4e36371.

Severity
4.6 (Medium)
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "coreutils",
            "binary_version": "8.21-1ubuntu5.4"
          },
          {
            "binary_name": "mktemp",
            "binary_version": "8.21-1ubuntu5.4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:14.04:LTS",
        "name": "coreutils",
        "purl": "pkg:deb/ubuntu/coreutils@8.21-1ubuntu5.4?arch=source\u0026distro=trusty"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "8.20-3ubuntu5",
        "8.21-1ubuntu3",
        "8.21-1ubuntu4",
        "8.21-1ubuntu5",
        "8.21-1ubuntu5.1",
        "8.21-1ubuntu5.3",
        "8.21-1ubuntu5.4"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "coreutils",
            "binary_version": "8.25-2ubuntu3~16.04"
          },
          {
            "binary_name": "mktemp",
            "binary_version": "8.25-2ubuntu3~16.04"
          },
          {
            "binary_name": "realpath",
            "binary_version": "8.25-2ubuntu3~16.04"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "coreutils",
        "purl": "pkg:deb/ubuntu/coreutils@8.25-2ubuntu3~16.04?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "8.23-4ubuntu2",
        "8.25-2ubuntu2",
        "8.25-2ubuntu3~16.04"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "coreutils",
            "binary_version": "8.28-1ubuntu1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "coreutils",
        "purl": "pkg:deb/ubuntu/coreutils@8.28-1ubuntu1?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "8.26-3ubuntu4",
        "8.28-1ubuntu1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "coreutils",
            "binary_version": "8.30-3ubuntu2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "coreutils",
        "purl": "pkg:deb/ubuntu/coreutils@8.30-3ubuntu2?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "8.30-3ubuntu2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "coreutils",
            "binary_version": "8.32-4.1ubuntu1.3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "coreutils",
        "purl": "pkg:deb/ubuntu/coreutils@8.32-4.1ubuntu1.3?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "8.32-4ubuntu2",
        "8.32-4ubuntu3",
        "8.32-4.1ubuntu1",
        "8.32-4.1ubuntu1.1",
        "8.32-4.1ubuntu1.2",
        "8.32-4.1ubuntu1.3"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "coreutils",
            "binary_version": "9.4-3ubuntu6.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "coreutils",
        "purl": "pkg:deb/ubuntu/coreutils@9.4-3ubuntu6.2?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "9.1-1ubuntu2",
        "9.4-2ubuntu1",
        "9.4-2ubuntu2",
        "9.4-2ubuntu3",
        "9.4-2ubuntu4",
        "9.4-3ubuntu3",
        "9.4-3ubuntu5",
        "9.4-3ubuntu6",
        "9.4-3ubuntu6.1",
        "9.4-3ubuntu6.2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "gnu-coreutils",
            "binary_version": "9.7-3ubuntu2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "coreutils",
        "purl": "pkg:deb/ubuntu/coreutils@9.7-3ubuntu2?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "9.5-1ubuntu4",
        "9.7-3ubuntu1",
        "9.7-3ubuntu2"
      ]
    }
  ],
  "aliases": [],
  "details": "GNU coreutils uniq is vulnerable to an out\u2011of\u2011bounds read due to incorrect handling of multibyte input when the -w (--check-chars) option is used. The find_field() function miscalculates the byte length of characters by repeatedly processing a fixed pointer instead of advancing through the input, resulting in an inflated length value. This incorrect length is later used in a memcmp operation, causing reads beyond the allocated buffer when processing crafted multibyte input. When running GNU coreutils uniq with attacker-provided arguments, this behavior leads to a crash and potential adjacent heap memory exposure. This issue has been fixed in the commit d64e35a8a4c0e4608321433e0d84d917e4e36371.",
  "id": "UBUNTU-CVE-2026-56391",
  "modified": "2026-07-29T07:59:16Z",
  "published": "2026-07-24T09:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-56391"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-56391"
    },
    {
      "type": "REPORT",
      "url": "https://www.openwall.com/lists/oss-security/2026/07/25/2"
    },
    {
      "type": "REPORT",
      "url": "https://cert.pl/en/posts/2026/07/CVE-2026-56391"
    },
    {
      "type": "REPORT",
      "url": "https://git.savannah.gnu.org/cgit/coreutils.git/"
    },
    {
      "type": "REPORT",
      "url": "https://git.savannah.gnu.org/cgit/coreutils.git/commit/?id=d64e35a8a4c0e4608321433e0d84d917e4e36371"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-56391"
  ]
}



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.