CVE-2026-34835

{
  "id": "CVE-2026-34835",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-34835",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-04-02T17:43:54.517566Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "security-advisories@github.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 4.8,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N",
          "integrityImpact": "LOW",
          "userInteraction": "NONE",
          "attackComplexity": "HIGH",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "LOW"
        },
        "impactScore": 2.5,
        "exploitabilityScore": 2.2
      },
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
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          "baseScore": 6.5,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
          "integrityImpact": "LOW",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "LOW"
        },
        "impactScore": 2.5,
        "exploitabilityScore": 3.9
      }
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  "affected": [
    {
      "source": "security-advisories@github.com",
      "affectedData": [
        {
          "vendor": "rack",
          "product": "rack",
          "versions": [
            {
              "status": "affected",
              "version": ">= 3.0.0.beta1, < 3.1.21"
            },
            {
              "status": "affected",
              "version": ">= 3.2.0, < 3.2.6"
            }
          ]
        }
      ]
    }
  ],
  "published": "2026-04-02T18:16:33.967",
  "references": [
    {
      "url": "https://github.com/rack/rack/security/advisories/GHSA-g2pf-xv49-m2h5",
      "tags": [
        "Exploit",
        "Mitigation",
        "Vendor Advisory"
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security-advisories@github.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-1286"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Rack is a modular Ruby web server interface. From versions 3.0.0.beta1 to before 3.1.21, and 3.2.0 to before 3.2.6, Rack::Request parses the Host header using an AUTHORITY regular expression that accepts characters not permitted in RFC-compliant hostnames, including /, ?, #, and @. Because req.host returns the full parsed value, applications that validate hosts using naive prefix or suffix checks can be bypassed. This can lead to host header poisoning in applications that use req.host, req.url, or req.base_url for link generation, redirects, or origin validation. This issue has been patched in versions 3.1.21 and 3.2.6."
    },
    {
      "lang": "es",
      "value": "Rack es una interfaz modular de servidor web Ruby. Desde las versiones 3.0.0.beta1 hasta antes de la 3.1.21, y de la 3.2.0 hasta antes de la 3.2.6, Rack::Request analiza el encabezado Host utilizando una expresión regular AUTHORITY que acepta caracteres no permitidos en nombres de host conformes a RFC, incluyendo /, ?, # y @. Debido a que req.host devuelve el valor analizado completo, las aplicaciones que validan hosts utilizando comprobaciones ingenuas de prefijo o sufijo pueden ser eludidas. Esto puede llevar a un envenenamiento del encabezado Host en aplicaciones que utilizan req.host, req.url o req.base_url para la generación de enlaces, redirecciones o validación de origen. Este problema ha sido parcheado en las versiones 3.1.21 y 3.2.6."
    }
  ],
  "lastModified": "2026-07-24T21:10:00.143",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
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              "criteria": "cpe:2.3:a:rack:rack:*:*:*:*:*:ruby:*:*",
              "vulnerable": true,
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              "versionEndExcluding": "3.1.21",
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  "sourceIdentifier": "security-advisories@github.com"
}