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BREW-MAILCATCHER-CVE-201… (GHSA-5R2P-J47H-MHPG)

Vulnerability from osv_homebrew – Published: 2026-08-13 17:11 – Updated: 2026-09-04 09:28 – Source website
VLAI
Summary
Rack vulnerable to Cross-site Scripting
Details

There is a possible XSS vulnerability in Rack before 2.0.6 and 1.6.11. Carefully crafted requests can impact the data returned by the scheme method on Rack::Request. Applications that expect the scheme to be limited to 'http' or 'https' and do not escape the return value could be vulnerable to an XSS attack. Note that applications using the normal escaping mechanisms provided by Rails may not impacted, but applications that bypass the escaping mechanisms, or do not use them may be vulnerable.

Severity
6.1 (Medium)
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": "bump",
        "range_state": "fixed",
        "resource": "rack",
        "resource_purl": "pkg:gem/rack@3.2.7",
        "upstream_fixed_in": "2.0.6"
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "mailcatcher",
        "purl": "pkg:brew/mailcatcher"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.10.0_2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "confidence": "high",
    "source": "matched",
    "strategy": "registry",
    "upstream_evidence": [
      {
        "ecosystem": "RubyGems",
        "key": "pkg:gem/rack@3.2.7",
        "name": "rack",
        "resource": "rack",
        "strategy": "registry",
        "subject_version": "3.2.7"
      }
    ]
  },
  "details": "There is a possible XSS vulnerability in Rack before 2.0.6 and 1.6.11. Carefully crafted requests can impact the data returned by the `scheme` method on `Rack::Request`. Applications that expect the scheme to be limited to \u0027http\u0027 or \u0027https\u0027 and do not escape the return value could be vulnerable to an XSS attack. Note that applications using the normal escaping mechanisms provided by Rails may not impacted, but applications that bypass the escaping mechanisms, or do not use them may be vulnerable.",
  "id": "BREW-mailcatcher-CVE-2018-16471",
  "modified": "2026-09-04T09:28:51Z",
  "published": "2026-08-13T17:11:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2018-16471"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/rack/rack"
    },
    {
      "type": "WEB",
      "url": "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/rack/CVE-2018-16471.yml"
    },
    {
      "type": "WEB",
      "url": "https://groups.google.com/forum/#!topic/ruby-security-ann/NAalCee8n6o"
    },
    {
      "type": "WEB",
      "url": "https://groups.google.com/forum/#!topic/rubyonrails-security/GKsAFT924Ag"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2018/11/msg00022.html"
    },
    {
      "type": "WEB",
      "url": "https://usn.ubuntu.com/4089-1"
    },
    {
      "type": "WEB",
      "url": "http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00032.html"
    },
    {
      "type": "WEB",
      "url": "http://lists.opensuse.org/opensuse-security-announce/2020-02/msg00016.html"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Rack vulnerable to Cross-site Scripting",
  "upstream": [
    "GHSA-5r2p-j47h-mhpg",
    "CVE-2018-16471"
  ]
}



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