CVE-2026-54064: NukeViet Cross-Site Scripting Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-465g-4q99-5x86",
  "modified" : "2026-07-13T17:54:08Z",
  "published" : "2026-07-13T17:54:08Z",
  "aliases" : [ "CVE-2026-54064" ],
  "summary" : "NukeViet: Multiple Anti-XSS Filter Bypasses Leading to Stored XSS in News Module",
  "details" : "## Summary\n\nTwo filter-bypass techniques in `NukeViet\\Core\\Request::filterAttr()` and `NukeViet\\Core\\Request::unhtmlentities()` allow a low-privileged user (any account with news post permission) to store and serve arbitrary JavaScript to any visitor of the affected page.\n\n## Affected Component\n\n`vendor/vinades/nukeviet/Core/Request.php` — class `NukeViet\\Core\\Request`\n\n## Vulnerability Details\n\n### Bypass 1 — Form Feed character prefix (`\\x0C`) before event handler name\n\nThe `filterAttr()` method blocks event-handler attributes using:\n```php\npreg_match('/^on/i', $attrSubSet[0])\n```\nPHP's `trim()` does **not** strip the ASCII Form Feed character (`\\x0C`, U+000C). An attacker can prefix the attribute name with `\\x0C` so that `\\x0Conerror` does not match `/^on/`. The HTML5 browser parser treats `\\x0C` as a valid whitespace separator and correctly activates the event handler.\n\n**Proof-of-concept payload (URL-encoded POST body field `bodyhtml`):**\n```\n<img src=\"x\" %0Conerror=\"alert('XSS')\">\n```\n\n### Bypass 2 — Decimal HTML entity tab (`&#9;`) inside `javascript:` URI\n\n`unhtmlentities()` strips the hex-encoded tab `&#x09;` via `str_ireplace`, but did **not** strip its decimal equivalent `&#9;`. The keyword-blocking regex `/j\\s*a\\s*v\\s*a\\s*s\\s*c\\s*r\\s*i\\s*p\\s*t/si` uses `\\s*` which does not match HTML entities. The value `jav&#9;ascript:alert()` passes the filter, is stored in the database, and is decoded by the browser into a working `javascript:` URI.\n\n**Proof-of-concept payload (inside a Markdown-style link):**\n```\n[Click me](jav&#9;ascript:alert('XSS'))\n```\n\n## Impact\n\nAn authenticated attacker with news-posting permission can inject persistent JavaScript that executes in the browser of **any user** (including administrators) who views the affected article. This enables session cookie theft, credential harvesting, defacement, and further privilege escalation.\n\n## Patches\n\nFixed in commit `<commit-sha>` by modifying `vendor/vinades/nukeviet/Core/Request.php`:\n\n1. **`filterAttr()`** — strip all ASCII control characters (`\\x00`–`\\x20`) from the attribute name before the `/^on/` check:\n   ```php\n   $attrSubSet[0] = preg_replace('/[\\x00-\\x20]/', '', strtolower($attrSubSet[0]));\n   ```\n\n2. **`unhtmlentities()`** — strip decimal HTML entities for all ASCII control characters (0–31) before the keyword checks:\n   ```php\n   $value = preg_replace('/&#0*(?:3[01]|[12][0-9]|[0-9]);/', '', $value);\n   ```\n\n## Workarounds\n\nNone. Update to the patched version.\n\n## Resources\n\n- CWE-79: Improper Neutralization of Input During Web Page Generation (Cross-site Scripting)\n- OWASP WSTG-INPV-02: Testing for Stored Cross Site Scripting\n- [OWASP Top 10 A03:2021 – Injection](https://owasp.org/Top10/A03_2021-Injection/)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "nukeviet/nukeviet"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "4.6.00"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/nukeviet/nukeviet/security/advisories/GHSA-465g-4q99-5x86"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/nukeviet/nukeviet"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-07-13T17:54:08Z",
    "nvd_published_at" : null
  }
}