ubuntu-cve-2026-29518
Vulnerability from osv_ubuntu
Published
2026-05-20 00:00
Modified
2026-06-30 16:19
Summary
Details

Rsync versions before 3.4.3 contain a time-of-check to time-of-use (TOCTOU) race condition in daemon file handling that allows attackers to redirect file writes outside intended directories by replacing parent directory components with symbolic links. Attackers with write access to a module path can exploit this race condition to create or overwrite arbitrary files, potentially modifying sensitive system files and achieving privilege escalation when the daemon runs with elevated privileges. This vulnerability can only be triggered if the chroot setting is false.

Severity
7.0 (High)
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8 (High)
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
7.3 (High)
CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
N/A (UNKNOWN)
high
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "rsync",
            "binary_version": "3.1.0-2ubuntu0.4+esm3"
          }
        ],
        "priority_reason": "rsync developers have rated this as being a high severity issue"
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:14.04:LTS",
        "name": "rsync",
        "purl": "pkg:deb/ubuntu/rsync@3.1.0-2ubuntu0.4+esm3?arch=source\u0026distro=esm-infra-legacy/trusty"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.1.0-2ubuntu0.4+esm3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.0.9-4ubuntu1",
        "3.1.0-2",
        "3.1.0-2ubuntu0.1",
        "3.1.0-2ubuntu0.2",
        "3.1.0-2ubuntu0.3",
        "3.1.0-2ubuntu0.4",
        "3.1.0-2ubuntu0.4+esm1",
        "3.1.0-2ubuntu0.4+esm2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "rsync",
            "binary_version": "3.1.1-3ubuntu1.3+esm5"
          }
        ],
        "priority_reason": "rsync developers have rated this as being a high severity issue"
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "rsync",
        "purl": "pkg:deb/ubuntu/rsync@3.1.1-3ubuntu1.3+esm5?arch=source\u0026distro=esm-infra-legacy/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.1.1-3ubuntu1.3+esm5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.1.1-3",
        "3.1.1-3ubuntu1",
        "3.1.1-3ubuntu1.1",
        "3.1.1-3ubuntu1.2",
        "3.1.1-3ubuntu1.3",
        "3.1.1-3ubuntu1.3+esm1",
        "3.1.1-3ubuntu1.3+esm2",
        "3.1.1-3ubuntu1.3+esm3",
        "3.1.1-3ubuntu1.3+esm4"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "rsync",
            "binary_version": "3.1.2-2.1ubuntu1.6+esm3"
          }
        ],
        "priority_reason": "rsync developers have rated this as being a high severity issue"
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "rsync",
        "purl": "pkg:deb/ubuntu/rsync@3.1.2-2.1ubuntu1.6+esm3?arch=source\u0026distro=esm-infra/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.1.2-2.1ubuntu1.6+esm3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.1.2-2",
        "3.1.2-2.1",
        "3.1.2-2.1ubuntu1",
        "3.1.2-2.1ubuntu1.1",
        "3.1.2-2.1ubuntu1.2",
        "3.1.2-2.1ubuntu1.3",
        "3.1.2-2.1ubuntu1.4",
        "3.1.2-2.1ubuntu1.5",
        "3.1.2-2.1ubuntu1.6",
        "3.1.2-2.1ubuntu1.6+esm1",
        "3.1.2-2.1ubuntu1.6+esm2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "rsync",
            "binary_version": "3.1.3-8ubuntu0.9+esm1"
          }
        ],
        "priority_reason": "rsync developers have rated this as being a high severity issue"
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "rsync",
        "purl": "pkg:deb/ubuntu/rsync@3.1.3-8ubuntu0.9+esm1?arch=source\u0026distro=esm-infra/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.1.3-8ubuntu0.9+esm1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.1.3-6",
        "3.1.3-8",
        "3.1.3-8ubuntu0.1",
        "3.1.3-8ubuntu0.2",
        "3.1.3-8ubuntu0.3",
        "3.1.3-8ubuntu0.4",
        "3.1.3-8ubuntu0.5",
        "3.1.3-8ubuntu0.7",
        "3.1.3-8ubuntu0.8",
        "3.1.3-8ubuntu0.9"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "rsync",
            "binary_version": "3.2.7-0ubuntu0.22.04.6"
          }
        ],
        "priority_reason": "rsync developers have rated this as being a high severity issue"
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "rsync",
        "purl": "pkg:deb/ubuntu/rsync@3.2.7-0ubuntu0.22.04.6?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.2.7-0ubuntu0.22.04.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.2.3-4ubuntu1",
        "3.2.3-4ubuntu2",
        "3.2.3-8ubuntu1",
        "3.2.3-8ubuntu2",
        "3.2.3-8ubuntu3",
        "3.2.3-8ubuntu3.1",
        "3.2.7-0ubuntu0.22.04.2",
        "3.2.7-0ubuntu0.22.04.3",
        "3.2.7-0ubuntu0.22.04.4"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "rsync",
            "binary_version": "3.2.7-1ubuntu1.4"
          }
        ],
        "priority_reason": "rsync developers have rated this as being a high severity issue"
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "rsync",
        "purl": "pkg:deb/ubuntu/rsync@3.2.7-1ubuntu1.4?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.2.7-1ubuntu1.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.2.7-1",
        "3.2.7-1build1",
        "3.2.7-1build2",
        "3.2.7-1ubuntu1",
        "3.2.7-1ubuntu1.1",
        "3.2.7-1ubuntu1.2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "rsync",
            "binary_version": "3.4.1+ds1-5ubuntu1.2"
          }
        ],
        "priority_reason": "rsync developers have rated this as being a high severity issue"
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "rsync",
        "purl": "pkg:deb/ubuntu/rsync@3.4.1+ds1-5ubuntu1.2?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.4.1+ds1-5ubuntu1.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.4.1+ds1-3",
        "3.4.1+ds1-4",
        "3.4.1+ds1-5",
        "3.4.1+ds1-5ubuntu1"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "rsync",
            "binary_version": "3.4.1+ds1-7ubuntu0.2"
          }
        ],
        "priority_reason": "rsync developers have rated this as being a high severity issue"
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "rsync",
        "purl": "pkg:deb/ubuntu/rsync@3.4.1+ds1-7ubuntu0.2?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.4.1+ds1-7ubuntu0.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.4.1+ds1-5ubuntu1",
        "3.4.1+ds1-6",
        "3.4.1+ds1-7"
      ]
    }
  ],
  "aliases": [],
  "details": "Rsync versions before 3.4.3 contain a time-of-check to time-of-use (TOCTOU) race condition in daemon file handling that allows attackers to redirect file writes outside intended directories by replacing parent directory components with symbolic links. Attackers with write access to a module path can exploit this race condition to create or overwrite arbitrary files, potentially modifying sensitive system files and achieving privilege escalation when the daemon runs with elevated privileges. This vulnerability can only be triggered if the chroot setting is false.",
  "id": "UBUNTU-CVE-2026-29518",
  "modified": "2026-06-30T16:19:41Z",
  "published": "2026-05-20T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-29518"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-29518"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8283-1"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8349-1"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8349-2"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8349-3"
    }
  ],
  "related": [
    "USN-8283-1",
    "USN-8349-1",
    "USN-8349-2",
    "USN-8349-3"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "high",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-29518"
  ]
}



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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

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.