FKIE_CVE-2026-31873

Vulnerability from fkie_nvd - Published: 2026-03-12 18:16 - Updated: 2026-03-16 17:57
Severity ?
0.0 (None) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N
6.1 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Summary
Unhead is a document head and template manager. Prior to 2.1.11, The link.href check in makeTagSafe (safe.ts) uses String.includes(), which is case-sensitive. Browsers treat URI schemes case-insensitively. DATA:text/css,... is the same as data:text/css,... to the browser, but 'DATA:...'.includes('data:') returns false. An attacker can inject arbitrary CSS for UI redressing or data exfiltration via CSS attribute selectors with background-image callbacks. This vulnerability is fixed in 2.1.11.
References
security-advisories@github.comhttps://github.com/unjs/unhead/security/advisories/GHSA-5339-hvwr-7582Exploit, Mitigation, Vendor Advisory
Impacted products
Vendor Product Version
unjs unhead *
To clipboard 

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  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:unjs:unhead:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "67F3AFEA-7DE2-46CC-AC50-D8B49F57C37E",
              "versionEndExcluding": "2.1.11",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
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    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Unhead is a document head and template manager. Prior to 2.1.11, The link.href check in makeTagSafe (safe.ts) uses String.includes(), which is case-sensitive. Browsers treat URI schemes case-insensitively. DATA:text/css,... is the same as data:text/css,... to the browser, but \u0027DATA:...\u0027.includes(\u0027data:\u0027) returns false. An attacker can inject arbitrary CSS for UI redressing or data exfiltration via CSS attribute selectors with background-image callbacks. This vulnerability is fixed in 2.1.11."
    },
    {
      "lang": "es",
      "value": "Unhead es un gestor de cabeceras de documento y plantillas. Antes de la versi\u00f3n 2.1.11, la comprobaci\u00f3n de link.href en makeTagSafe (safe.ts) utiliza String.includes(), que distingue entre may\u00fasculas y min\u00fasculas. Los navegadores tratan los esquemas URI sin distinguir entre may\u00fasculas y min\u00fasculas. DATA:text/css,... es lo mismo que data:text/css,... para el navegador, pero \u0027DATA:...\u0027.includes(\u0027data:\u0027) devuelve falso. Un atacante puede inyectar CSS arbitrario para la manipulaci\u00f3n de la interfaz de usuario o la exfiltraci\u00f3n de datos a trav\u00e9s de selectores de atributos CSS con retrollamadas de background-image. Esta vulnerabilidad se corrige en la versi\u00f3n 2.1.11."
    }
  ],
  "id": "CVE-2026-31873",
  "lastModified": "2026-03-16T17:57:01.537",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 0.0,
          "baseSeverity": "NONE",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N",
          "version": "3.1"
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        "impactScore": 0.0,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      },
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.1,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "LOW",
          "privilegesRequired": "NONE",
          "scope": "CHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 2.7,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ]
  },
  "published": "2026-03-12T18:16:24.387",
  "references": [
    {
      "source": "security-advisories@github.com",
      "tags": [
        "Exploit",
        "Mitigation",
        "Vendor Advisory"
      ],
      "url": "https://github.com/unjs/unhead/security/advisories/GHSA-5339-hvwr-7582"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}


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