FKIE_CVE-2026-27120

Vulnerability from fkie_nvd - Published: 2026-02-20 22:16 - Updated: 2026-02-23 18:14
Severity ?
6.1 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Summary
Leafkit is a templating language with Swift-inspired syntax. Prior to 1.4.1, htmlEscaped in leaf-kit will only escape html special characters if the extended grapheme clusters match, which allows bypassing escaping by using an extended grapheme cluster containing both the special html character and some additional characters. In the case of html attributes, this can lead to XSS if there is a leaf variable in the attribute that is user controlled. This vulnerability is fixed in 1.4.1.
References
security-advisories@github.comhttps://github.com/vapor/leaf-kit/commit/8919e39476c3a4ba05c28b71546bb9195f87ef34
security-advisories@github.comhttps://github.com/vapor/leaf-kit/security/advisories/GHSA-4hfh-fch3-5q7p
Impacted products
Vendor Product Version
To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Leafkit is a templating language with Swift-inspired syntax. Prior to 1.4.1, htmlEscaped in leaf-kit will only escape html special characters if the extended grapheme clusters match, which allows bypassing escaping by using an extended grapheme cluster containing both the special html character and some additional characters. In the case of html attributes, this can lead to XSS if there is a leaf variable in the attribute that is user controlled. This vulnerability is fixed in 1.4.1."
    },
    {
      "lang": "es",
      "value": "Leafkit es un lenguaje de plantillas con sintaxis inspirada en Swift. Antes de la versi\u00f3n 1.4.1, htmlEscaped en leaf-kit solo escapar\u00e1 los caracteres especiales HTML si los cl\u00fasteres de grafemas extendidos coinciden, lo que permite eludir el escape utilizando un cl\u00faster de grafemas extendido que contenga tanto el car\u00e1cter especial HTML como algunos caracteres adicionales. En el caso de los atributos HTML, esto puede llevar a XSS si hay una variable leaf en el atributo que est\u00e1 controlada por el usuario. Esta vulnerabilidad est\u00e1 corregida en la versi\u00f3n 1.4.1."
    }
  ],
  "id": "CVE-2026-27120",
  "lastModified": "2026-02-23T18:14:13.887",
  "metrics": {
    "cvssMetricV31": [
      {
        "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": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-02-20T22:16:29.830",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/vapor/leaf-kit/commit/8919e39476c3a4ba05c28b71546bb9195f87ef34"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/vapor/leaf-kit/security/advisories/GHSA-4hfh-fch3-5q7p"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Undergoing Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-75"
        },
        {
          "lang": "en",
          "value": "CWE-79"
        },
        {
          "lang": "en",
          "value": "CWE-87"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}


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