GHSA-FMQH-3QCQ-WCXG

Vulnerability from github – Published: 2026-07-09 09:30 – Updated: 2026-07-09 09:30
VLAI
Details

The Ultimate Post plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'moreResultsText' block attribute of the ultimate-post/advanced-search block in versions up to and including 5.0.31. This is due to insufficient input sanitization and output escaping in the Advanced_Search::content() render callback: the attribute value is filtered with wp_kses(), which strips disallowed HTML tags but does NOT escape HTML special characters such as double quotes in plain text, and the result is then concatenated directly into the data-viewmoretext HTML attribute without esc_attr(). This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

Severity
6.4 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2026-13253"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-09T08:16:46Z",
    "severity": "MODERATE"
  },
  "details": "The Ultimate Post plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the \u0027moreResultsText\u0027 block attribute of the ultimate-post/advanced-search block in versions up to and including 5.0.31. This is due to insufficient input sanitization and output escaping in the Advanced_Search::content() render callback: the attribute value is filtered with wp_kses(), which strips disallowed HTML tags but does NOT escape HTML special characters such as double quotes in plain text, and the result is then concatenated directly into the data-viewmoretext HTML attribute without esc_attr(). This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.",
  "id": "GHSA-fmqh-3qcq-wcxg",
  "modified": "2026-07-09T09:30:28Z",
  "published": "2026-07-09T09:30:28Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-13253"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/ultimate-post/tags/5.0.27/blocks/Advanced_Search.php#L108"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/ultimate-post/tags/5.0.27/blocks/Advanced_Search.php#L116"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/ultimate-post/tags/5.0.27/classes/Blocks.php#L231"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/ultimate-post/tags/5.0.28/blocks/Advanced_Search.php#L108"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/ultimate-post/tags/5.0.28/blocks/Advanced_Search.php#L116"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/ultimate-post/tags/5.0.28/classes/Blocks.php#L231"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/changeset?reponame=\u0026old=3598669%40ultimate-post\u0026new=3598669%40ultimate-post"
    },
    {
      "type": "WEB",
      "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/070ccd70-22c3-47f1-9dce-a884bff9ea76?source=cve"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.