CVE-2020-4054: Sanitize Cross-Site Scripting Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-p4x4-rw2p-8j8m",
  "modified" : "2023-05-16T16:18:26Z",
  "published" : "2020-06-16T22:08:06Z",
  "aliases" : [ "CVE-2020-4054" ],
  "summary" : "Cross-site Scripting in Sanitize ",
  "details" : "When HTML is sanitized using Sanitize's \"relaxed\" config or a custom config that allows certain elements, some content in a `<math>` or `<svg>` element may not be sanitized correctly even if `math` and `svg` are not in the allowlist.\n\nYou are likely to be vulnerable to this issue if you use Sanitize's relaxed config or a custom config that allows one or more of the following HTML elements:\n\n- `iframe`\n- `math`\n- `noembed`\n- `noframes`\n- `noscript`\n- `plaintext`\n- `script`\n- `style`\n- `svg`\n- `xmp`\n\n### Impact\n\nUsing carefully crafted input, an attacker may be able to sneak arbitrary HTML through Sanitize, potentially resulting in XSS (cross-site scripting) or other undesired behavior when that HTML is rendered in a browser.\n\n### Releases\n\nThis problem has been fixed in Sanitize 5.2.1.\n\n### Workarounds\n\nIf upgrading is not possible, a workaround is to override the default value of Sanitize's `:remove_contents` config option with the following value, which ensures that the contents of `math` and `svg` elements (among others) are removed entirely when those elements are not in the allowlist:\n\n```ruby\n%w[iframe math noembed noframes noscript plaintext script style svg xmp]\n```\n\nFor example, if you currently use Sanitize's relaxed config, you can create a custom config object that overrides the default value of `:remove_contents` like this:\n\n```ruby\ncustom_config = Sanitize::Config.merge(\n  Sanitize::Config::RELAXED,\n  :remove_contents => %w[iframe math noembed noframes noscript plaintext script style svg xmp]\n)\n```\n\nYou would then pass this custom config to Sanitize when sanitizing HTML.\n\n### For more information\n\nIf you have any questions or comments about this advisory:\n\n- Open an issue in the [Sanitize repo](https://github.com/rgrove/sanitize).\n- See Sanitize's [security policy](https://github.com/rgrove/sanitize/security/policy).\n\n### Credits\n\nMany thanks to Michal Bentkowski of Securitum for reporting this bug and helping to verify the fix.\n\n### References\n\n- [GHSA-p4x4-rw2p-8j8m](https://github.com/rgrove/sanitize/security/advisories/GHSA-p4x4-rw2p-8j8m)\n- [CVE-2020-4054](https://nvd.nist.gov/vuln/detail/CVE-2020-4054)\n- https://github.com/rgrove/sanitize/releases/tag/v5.2.1",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "RubyGems",
      "name" : "sanitize"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "3.0.0"
      }, {
        "fixed" : "5.2.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/rgrove/sanitize/security/advisories/GHSA-p4x4-rw2p-8j8m"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-4054"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rgrove/sanitize/commit/a11498de9e283cd457b35ee252983662f7452aa9"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/rgrove/sanitize"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rgrove/sanitize/releases/tag/v5.2.1"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/sanitize/CVE-2020-4054.yml"
  }, {
    "type" : "WEB",
    "url" : "https://usn.ubuntu.com/4543-1"
  }, {
    "type" : "WEB",
    "url" : "https://www.debian.org/security/2020/dsa-4730"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2020-06-16T21:42:41Z",
    "nvd_published_at" : null
  }
}