CVE-2026-39575
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 · uneditedImproper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Ronald Huereca Custom Query Blocks post-type-archive-mapping allows DOM-Based XSS.This issue affects Custom Query Blocks: from n/a through <= 5.5.0.
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 confidenceDOM-based Cross-site Scripting (XSS) vulnerability in the Custom Query Blocks WordPress plugin's post-type-archive-mapping feature. The plugin fails to properly sanitize user-controlled input before using it in DOM manipulation, allowing attackers to inject malicious scripts that execute in victims' browsers.
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
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:L/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 checksWork through these to decide whether this CVE applies to you.
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Confirm Custom Query Blocks plugin is installedNavigate to WordPress admin plugins page and locate 'Custom Query Blocks' in the installed plugins list, or check the plugins directory for the Custom Query Blocks plugin filesAffected if The plugin is installed and active in the WordPress environment
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Identify the installed plugin versionCheck the plugin header in main plugin file (usually in wp-content/plugins/custom-query-blocks/ directory) for the Version field, or view the plugin details in WordPress admin plugins listAffected if Version is within the affected range or cannot be determined (treat as potentially vulnerable)
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Locate post-type-archive-mapping configurationNavigate to plugin settings or Custom Post Type/Query settings in WordPress admin where archive mapping is configured. Check for any post-type-archive-mapping options or custom query blocks that reference archive pagesAffected if post-type-archive-mapping feature is enabled or has been configured with custom values
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Inspect input fields in archive mapping for unsanitized outputView the page source (browser DevTools > Elements) while on any WordPress archive page created or influenced by Custom Query Blocks. Look for archive URLs, post type names, or query parameters rendered directly into HTML without proper encoding (look for unescaped < > " characters in attributes or text content)Affected if User-supplied values in archive mapping appear raw or improperly escaped in the DOM
Environment is affected if Custom Query Blocks plugin is installed with post-type-archive-mapping enabled and archive-related values render without proper HTML encoding in the browser
Generated from the published advisory. Verify against your own configuration.
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 dataUpdate Custom Query Blocks to a version beyond 5.5.0 if available; otherwise, disable the plugin until a patched version is released. The fix requires adding proper output encoding and input validation in the post-type-archive-mapping code path.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-39575 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-39575 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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