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

CVE-2026-42739

HIGH · 7.1 CVSS v3.1 Published 2026-05-27
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
78/100
Remediation priority · High
Remotely reachable No privileges

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
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in IniLerm Advanced IP Blocker advanced-ip-blocker allows DOM-Based XSS.This issue affects Advanced IP Blocker: from n/a through <= 8.10.7.

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 · moderate confidence

A DOM-based Cross-Site Scripting (XSS) vulnerability exists in the IniLerm Advanced IP Blocker plugin where user-supplied input is not properly neutralized before being inserted into the web page's Document Object Model (DOM). This allows attackers to inject malicious JavaScript that executes in the victim's browser when the crafted payload is rendered.

MitigationThe vulnerability can be remediated by implementing proper input validation and output encoding when handling user data before inserting it into the DOM. Developers should identify the vulnerable JavaScript code path and apply context-aware sanitization or use safe DOM APIs that automatically encode 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
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
Low

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

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. Verify Advanced IP Blocker plugin is installed
    Locate the plugin directory in the web application's plugin folder (typically /wp-content/plugins/advanced-ip-blocker or similar naming pattern) and check for the main plugin file containing the version header.
    Affected if The plugin files exist on the server.
  2. Identify installed plugin version
    Open the main plugin PHP file and locate the Version header in the plugin comment block, or check the plugin database entry if accessible via CMS admin interface.
    Affected if No version or a version without the fix is found.
  3. Inspect JavaScript files for DOM manipulation code
    Search within the plugin folder for JavaScript files (*.js) that contain DOM insertion methods such as innerHTML, insertAdjacentHTML, document.write, or jQuery html() that handle user-supplied input without visible sanitization functions.
    Affected if JavaScript code inserts user input directly into the DOM using unsafe methods.
  4. Identify user input sources feeding the vulnerable DOM code
    Trace the data flow from HTTP request parameters (GET/POST) or URL fragments to the identified vulnerable DOM manipulation code. Look for references to $_GET, $_POST, or URL parameters used in the JavaScript.
    Affected if User-controlled input from URL parameters or form data flows directly to DOM insertion methods without apparent encoding.
  5. Confirm the plugin handles IP-related user data in the frontend
    Check if the plugin exposes any frontend-facing pages or AJAX endpoints that display user-provided IP addresses, block messages, or logging data that gets rendered in the browser.
    Affected if The plugin displays user-supplied data (such as IP addresses or custom block messages) on pages accessible to visitors.

If the plugin is installed and its JavaScript code directly inserts user-supplied input into the DOM without encoding, the environment is affected by this DOM-based XSS vulnerability.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

The vulnerability can be remediated by implementing proper input validation and output encoding when handling user data before inserting it into the DOM. Developers should identify the vulnerable JavaScript code path and apply context-aware sanitization or use safe DOM APIs that automatically encode content.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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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-2026-42739 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

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