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Cross-site Scripting (XSS)Weakness · CWE-79

CVE-2026-13253

MEDIUM · 6.4 CVSS v3.1 Published 2026-07-09
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
70/100
Remediation priority · Elevated
Remotely reachable Zero-click 6 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The Ultimate Post WordPress plugin fails to escape the 'moreResultsText' block attribute when rendering the advanced-search block. Although wp_kses() removes disallowed HTML tags, it does not encode HTML special characters like double quotes. The unescaped value is directly inserted into a data-viewmoretext HTML attribute without esc_attr(), allowing attribute injection for stored XSS. An attacker with contributor-level access can inject malicious JavaScript that executes when users view the affected page.

MitigationUpdate Ultimate Post plugin to version 5.0.32 or later. Until then, restrict contributor-level user permissions and review pages using the advanced-search block for suspicious content.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Confirm Ultimate Post plugin is installed
    Navigate to WordPress admin > Plugins > Installed Plugins, or inspect the /wp-content/plugins/ directory for a folder named 'ultimate-post'
    Affected if The Ultimate Post plugin appears in the plugins list
  2. Identify installed plugin version
    In the plugins list, locate the Ultimate Post plugin version number, or check the plugin's main PHP file (usually ultimate-post.php) for the 'Version' header in the file comment
    Affected if The version number is lower than 5.0.32
  3. Locate pages using the advanced-search block
    Search the WordPress database in wp_posts for content containing 'wp:UltimatePost/advanced-search' or use a block explorer plugin to find all instances of the advanced-search block
    Affected if Any posts or pages contain the advanced-search block
  4. Inspect moreResultsText block attribute
    For each page using advanced-search, export or view the block content and locate the 'moreResultsText' attribute value within the block markup
    Affected if The moreResultsText attribute contains unescaped HTML special characters, especially unescaped double quotes or script tags

The environment is affected if Ultimate Post plugin version is below 5.0.32 AND any page uses the advanced-search block with a moreResultsText attribute containing potentially malicious content

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update Ultimate Post plugin to version 5.0.32 or later. Until then, restrict contributor-level user permissions and review pages using the advanced-search block for suspicious content.

Recommended fix Moderate confidence

Latest version after 5.0.31 (check wordpress.org for current stable release)

  1. 1. Navigate to the WordPress admin dashboard
  2. 2. Go to Plugins > Installed Plugins
  3. 3. Locate the 'Ultimate Post' plugin
  4. 4. Check the current installed version (should be 5.0.31 or lower)
  5. 5. If an update is available, click 'Update Now' to install the latest version which contains the fix
  6. 6. Alternatively, download the latest version from wordpress.org/plugins/ultimate-post/ and upload via Plugins > Add New > Upload Plugin
  7. 7. After updating, verify the fix by confirming the moreResultsText block attribute now properly escapes HTML special characters using esc_attr()

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
5.0 hours of engineering $860
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-13253 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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