Vulnerability-Lookup

usn-8229-2

Vulnerability from osv_ubuntu

Published

2026-05-28 18:34

Modified

2026-05-28 18:34

Summary

sed vulnerability

Details

USN-8229-1 fixed a vulnerability in sed. This update provides the corresponding update for Ubuntu 18.04 LTS and Ubuntu 20.04 LTS.

Original advisory details:

Michał Majchrowicz and Marcin Wyczechowski discovered that sed incorrectly handled symbolic links when performing in-place edits. A local attacker could possibly use this issue to overwrite arbitrary files.

References

URL

Type

	https://ubuntu.com/security/notices/USN-8229-2	ADVISORY
	https://ubuntu.com/security/CVE-2026-5958	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2026-5958",
              "severity": [
                {
                  "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N",
                  "type": "CVSS_V4"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:Pro:18.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "sed",
            "binary_version": "4.4-2ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "sed",
        "purl": "pkg:deb/ubuntu/sed@4.4-2ubuntu0.1~esm1?arch=source\u0026distro=esm-infra/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.4-2ubuntu0.1~esm1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.4-1",
        "4.4-2"
      ]
    },
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2026-5958",
              "severity": [
                {
                  "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N",
                  "type": "CVSS_V4"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:Pro:20.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "sed",
            "binary_version": "4.7-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "sed",
        "purl": "pkg:deb/ubuntu/sed@4.7-1ubuntu0.1~esm1?arch=source\u0026distro=esm-infra/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.7-1ubuntu0.1~esm1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.7-1"
      ]
    }
  ],
  "aliases": [],
  "details": "USN-8229-1 fixed a vulnerability in sed. This update provides the\ncorresponding update for Ubuntu 18.04 LTS and Ubuntu 20.04 LTS.\n\nOriginal advisory details:\n\n Micha\u0142 Majchrowicz and Marcin Wyczechowski discovered that sed\n incorrectly handled symbolic links when performing in-place edits.\n A local attacker could possibly use this issue to overwrite\n arbitrary files.",
  "id": "USN-8229-2",
  "modified": "2026-05-28T18:34:13Z",
  "published": "2026-05-28T18:34:13Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8229-2"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-5958"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "summary": "sed vulnerability",
  "upstream": [
    "UBUNTU-CVE-2026-5958"
  ]
}

ubuntu-cve-2026-5958

Vulnerability from osv_ubuntu

Published

2026-04-19 00:00

Modified

2026-05-29 10:28

Summary

Details

When sed is invoked with both -i (in-place edit) and --follow-symlinks, the function open_next_file() performs two separate, non-atomic filesystem operations on the same path: 1. resolves symlink to its target and stores the resolved path for determining when output is written, 2. opens the original symlink path (not the resolved one) to read the file. Between these two calls there is a race window. If an attacker atomically replaces the symlink with a different target during that window, sed will: read content from the new (attacker-chosen) symlink target and write the processed result to the path recorded in step 1. This can lead to arbitrary file overwrite with attacker-controlled content in the context of the sed process. This issue was fixed in version 4.10.

Severity

2.1 (Low)


                    
                      CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-5958	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-5958	REPORT
	https://ubuntu.com/security/notices/USN-8229-1	ADVISORY
	https://ubuntu.com/security/notices/USN-8229-2	ADVISORY

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "sed",
            "binary_version": "4.4-2ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "sed",
        "purl": "pkg:deb/ubuntu/sed@4.4-2ubuntu0.1~esm1?arch=source\u0026distro=esm-infra/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.4-2ubuntu0.1~esm1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.4-1",
        "4.4-2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "sed",
            "binary_version": "4.7-1ubuntu0.1~esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "sed",
        "purl": "pkg:deb/ubuntu/sed@4.7-1ubuntu0.1~esm1?arch=source\u0026distro=esm-infra/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.7-1ubuntu0.1~esm1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.7-1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "sed",
            "binary_version": "4.8-1ubuntu2.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "sed",
        "purl": "pkg:deb/ubuntu/sed@4.8-1ubuntu2.1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.8-1ubuntu2.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.7-1ubuntu1",
        "4.7-1ubuntu2",
        "4.8-1ubuntu1",
        "4.8-1ubuntu2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "sed",
            "binary_version": "4.9-2ubuntu0.24.04.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "sed",
        "purl": "pkg:deb/ubuntu/sed@4.9-2ubuntu0.24.04.1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.9-2ubuntu0.24.04.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.9-1",
        "4.9-2",
        "4.9-2build1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "sed",
            "binary_version": "4.9-2ubuntu0.25.10.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "sed",
        "purl": "pkg:deb/ubuntu/sed@4.9-2ubuntu0.25.10.1?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.9-2ubuntu0.25.10.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.9-2build1",
        "4.9-2build2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "sed",
            "binary_version": "4.9-2ubuntu1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "sed",
        "purl": "pkg:deb/ubuntu/sed@4.9-2ubuntu1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.9-2ubuntu1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.9-2build2",
        "4.9-2build3"
      ]
    }
  ],
  "aliases": [],
  "details": "When sed is invoked with both -i (in-place edit) and --follow-symlinks, the function open_next_file() performs two separate, non-atomic filesystem operations on the same path: 1. resolves symlink to its target and stores\u00a0the resolved path for determining when output is written, 2. opens the original symlink path\u00a0(not the resolved one) to read the file. Between these two calls there is a race window. If an attacker atomically replaces the symlink with a different target during that window, sed will: read content from the new (attacker-chosen) symlink target and write the processed result to the path recorded in step 1.\u00a0This can lead to arbitrary file overwrite with attacker-controlled content in the context of the sed process. This issue was fixed in version 4.10.",
  "id": "UBUNTU-CVE-2026-5958",
  "modified": "2026-05-29T10:28:48Z",
  "published": "2026-04-19T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-5958"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-5958"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8229-1"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8229-2"
    }
  ],
  "related": [
    "USN-8229-1",
    "USN-8229-2"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-5958"
  ]
}

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.

Action not permitted

usn-8229-2

Vulnerability from osv_ubuntu

ubuntu-cve-2026-5958

Vulnerability from osv_ubuntu

Tags

Sightings

Nomenclature