RPB Chessboard <= 8.1.2 - Unauthenticated Stored Cross-Site Scripting via Comment Content
The RPB Chessboard plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Comment Content in all versions up to, and including, 8.1.2 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. WordPress's save-time kses sanitization does not mitigate this issue because the crafted payload uses only kses-allowed tags and attributes (such as an <a> element with title and href), and the dangerous attribute-breaking HTML is synthesized entirely at render time by the plugin's own comment_text filter.
Quick answer
RPB Chessboard should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- *-8.1.2
Fixed versions
- 8.1.3
How to fix it
RPB Chessboard is affected by this security issue. The safest fix is to update to the fixed version, then test the site or service again to make sure the risky path is closed.
- Find every place where RPB Chessboard is installed or used.
- Update to 8.1.3 or a later vendor-supported version.
- Back up the site or service before changing production systems.
- Apply the update in staging first if possible, then deploy it to production.
- If you cannot update right away, restrict access to the affected feature and monitor logs closely.
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Verify the fix
- Confirm the installed version or configuration is no longer in the affected range.
- Retest the affected page, API, plugin, workflow, or network path.
- Check logs after the change for blocked attempts, crashes, or errors.
- Run a fresh Fixnx scan and save the report.
Related categories
Trusted references
FAQ
What is affected by CVE-2026-13042?
RPB Chessboard versions listed as affected should be reviewed: *-8.1.2.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.