GHSA-RCQX-6Q8C-2C42

Vulnerability from github – Published: 2026-05-14 20:29 – Updated: 2026-06-09 18:41
VLAI
Summary
Svelte Vulnerable to XSS via DOM Clobbering of Internal Framework State
Details

Svelte was vulnerable to DOM clobbering of its internal framework state on elements, potentially leading to XSS attacks.

You are vulnerable if all of the following is true: - you are using attribute spreading on a form element - you are using attribute spreading or allow a dynamic value for the name attribute on an input or button element within that form - both of these are simultaneously user-controllable

<form {...spread1}>
  <input {...spread2}>
</form>
Severity
5.3 (Medium)
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:N/VA:N/SC:H/SI:H/SA:N
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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 5.55.6"
      },
      "package": {
        "ecosystem": "npm",
        "name": "svelte"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5.55.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-42573"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-14T20:29:13Z",
    "nvd_published_at": "2026-06-09T17:17:07Z",
    "severity": "MODERATE"
  },
  "details": "Svelte was vulnerable to DOM clobbering of its internal framework state on elements, potentially leading to XSS attacks.\n\nYou are vulnerable if all of the following is true:\n- you are using attribute spreading on a form element\n- you are using attribute spreading or allow a dynamic value for the `name` attribute on an input or button element within that form\n- both of these are simultaneously user-controllable\n\n```svelte\n\u003cform {...spread1}\u003e\n  \u003cinput {...spread2}\u003e\n\u003c/form\u003e\n```",
  "id": "GHSA-rcqx-6q8c-2c42",
  "modified": "2026-06-09T18:41:27Z",
  "published": "2026-05-14T20:29:13Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/sveltejs/svelte/security/advisories/GHSA-rcqx-6q8c-2c42"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42573"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/sveltejs/svelte"
    },
    {
      "type": "WEB",
      "url": "https://github.com/sveltejs/svelte/releases/tag/svelte%405.55.7"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:N/VA:N/SC:H/SI:H/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Svelte Vulnerable to XSS via DOM Clobbering of Internal Framework State"
}


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