ubuntu-cve-2026-73491
Vulnerability from osv_ubuntu
Published
2026-08-12 21:17
Modified
2026-08-19 11:11
Summary
Details

Loofah is a general library for manipulating and transforming HTML/XML documents and fragments, built on top of Nokogiri. From 2.25.0 until 2.25.2, Loofah::HTML5::Scrub.allowed_uri? does not reject javascript: URIs whose scheme is split or prefixed with the HTML5 named whitespace character references or . CGI.unescapeHTML leaves those references intact, so allowed_uri? reports the URL safe even though a browser decodes and strips the tab or line feed and executes the resulting javascript: URL. This issue affects only callers that pass HTML-encoded strings directly to allowed_uri?; Loofah's default sanitize() path is not affected. This issue is fixed in version 2.25.2.

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

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "ruby-loofah",
            "binary_version": "2.0.3-2+deb9u3build0.16.04.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "ruby-loofah",
        "purl": "pkg:deb/ubuntu/ruby-loofah@2.0.3-2+deb9u3build0.16.04.1?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.0.2-1",
        "2.0.3-1",
        "2.0.3-2",
        "2.0.3-2+deb9u1build0.16.04.1",
        "2.0.3-2+deb9u2build0.16.04.1",
        "2.0.3-2+deb9u3build0.16.04.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "ruby-loofah",
            "binary_version": "2.2.2-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "ruby-loofah",
        "purl": "pkg:deb/ubuntu/ruby-loofah@2.2.2-1?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.0.3-2",
        "2.2.2-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "ruby-loofah",
            "binary_version": "2.4.0+dfsg-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "ruby-loofah",
        "purl": "pkg:deb/ubuntu/ruby-loofah@2.4.0+dfsg-1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.2.3-1",
        "2.3.1+dfsg-1",
        "2.4.0+dfsg-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "ruby-loofah",
            "binary_version": "2.13.0-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "ruby-loofah",
        "purl": "pkg:deb/ubuntu/ruby-loofah@2.13.0-2?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.12.0-1",
        "2.13.0-1",
        "2.13.0-2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "ruby-loofah",
            "binary_version": "2.22.0-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "ruby-loofah",
        "purl": "pkg:deb/ubuntu/ruby-loofah@2.22.0-1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.21.3-1",
        "2.21.4-1",
        "2.22.0-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "ruby-loofah",
            "binary_version": "2.25.0-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "ruby-loofah",
        "purl": "pkg:deb/ubuntu/ruby-loofah@2.25.0-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "2.24.1-1",
        "2.25.0-1"
      ]
    }
  ],
  "aliases": [],
  "details": "Loofah is a general library for manipulating and transforming HTML/XML documents and fragments, built on top of Nokogiri. From 2.25.0 until 2.25.2, Loofah::HTML5::Scrub.allowed_uri? does not reject javascript: URIs whose scheme is split or prefixed with the HTML5 named whitespace character references \u0026Tab; or \u0026NewLine;. CGI.unescapeHTML leaves those references intact, so allowed_uri? reports the URL safe even though a browser decodes and strips the tab or line feed and executes the resulting javascript: URL. This issue affects only callers that pass HTML-encoded strings directly to allowed_uri?; Loofah\u0027s default sanitize() path is not affected. This issue is fixed in version 2.25.2.",
  "id": "UBUNTU-CVE-2026-73491",
  "modified": "2026-08-19T11:11:14Z",
  "published": "2026-08-12T21:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-73491"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-73491"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/flavorjones/loofah/security/advisories/GHSA-8whx-365g-h9vv"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/flavorjones/loofah/pull/308"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/flavorjones/loofah/commit/5e91af861e3cdab47b91dd0b81f3afdfd13a5e19"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/flavorjones/loofah/releases/tag/v2.25.2"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-73491"
  ]
}



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.