GHSA-MHWM-JH88-3GJF

Vulnerability from github – Published: 2025-03-03 22:05 – Updated: 2025-11-04 00:32
VLAI?
Summary
CGI has Regular Expression Denial of Service (ReDoS) potential in Util#escapeElement
Details

There is a possibility for Regular expression Denial of Service (ReDoS) by in the cgi gem. This vulnerability has been assigned the CVE identifier CVE-2025-27220. We recommend upgrading the cgi gem.

Details

The regular expression used in CGI::Util#escapeElement is vulnerable to ReDoS. The crafted input could lead to a high CPU consumption.

This vulnerability only affects Ruby 3.1 and 3.2. If you are using these versions, please update CGI gem to version 0.3.5.1, 0.3.7, 0.4.2 or later.

Affected versions

cgi gem versions <= 0.3.5, 0.3.6, 0.4.0 and 0.4.1.

Credits

Thanks to svalkanov for discovering this issue. Also thanks to nobu for fixing this vulnerability.

Severity ?
4.0 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:L
6.3 (Medium)
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "RubyGems",
        "name": "cgi"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.3.5.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "RubyGems",
        "name": "cgi"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.3.6"
            },
            {
              "fixed": "0.3.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.3.6"
      ]
    },
    {
      "package": {
        "ecosystem": "RubyGems",
        "name": "cgi"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.4.0"
            },
            {
              "fixed": "0.4.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-27220"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1333"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-03-03T22:05:08Z",
    "nvd_published_at": "2025-03-04T00:15:31Z",
    "severity": "MODERATE"
  },
  "details": "There is a possibility for Regular expression Denial of Service (ReDoS) by in the cgi gem. This vulnerability has been assigned the CVE identifier CVE-2025-27220. We recommend upgrading the cgi gem.\n\n## Details\n\nThe regular expression used in `CGI::Util#escapeElement` is vulnerable to ReDoS. The crafted input could lead to a high CPU consumption.\n\nThis vulnerability only affects Ruby 3.1 and 3.2. If you are using these versions, please update CGI gem to version 0.3.5.1, 0.3.7, 0.4.2 or later.\n\n## Affected versions\n\ncgi gem versions \u003c= 0.3.5, 0.3.6, 0.4.0 and 0.4.1.\n\n## Credits\n\nThanks to svalkanov for discovering this issue.\nAlso thanks to nobu for fixing this vulnerability.",
  "id": "GHSA-mhwm-jh88-3gjf",
  "modified": "2025-11-04T00:32:21Z",
  "published": "2025-03-03T22:05:08Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-27220"
    },
    {
      "type": "WEB",
      "url": "https://github.com/ruby/cgi/pull/52"
    },
    {
      "type": "WEB",
      "url": "https://github.com/ruby/cgi/pull/53"
    },
    {
      "type": "WEB",
      "url": "https://github.com/ruby/cgi/pull/54"
    },
    {
      "type": "WEB",
      "url": "https://hackerone.com/reports/2890322"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/ruby/cgi"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/cgi/CVE-2025-27220.yml"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00008.html"
    },
    {
      "type": "WEB",
      "url": "https://www.cve.org/CVERecord?id=CVE-2025-27220"
    },
    {
      "type": "WEB",
      "url": "https://www.ruby-lang.org/en/news/2025/02/26/security-advisories"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:L",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "CGI has Regular Expression Denial of Service (ReDoS) potential in Util#escapeElement"
}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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