RPB Chessboard <= 8.1.2 - Unauthenticated Stored Cross-Site Scripting via Comment Content
Strategic Overview
- Status
- Patched in 8.1.3
- Affected Plugin
- RPB Chessboard
- Affected Version
<= 8.1.2- CVSS
- 7.2High
- Weakness type
- CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- CVE
CVE-2026-13042
At a glance
CVE-2026-13042 is a high-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the RPB Chessboard WordPress plugin, affecting versions <= 8.1.2. It carries a CVSS score of 7.2 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 8.1.3; sites on affected versions should update now. Disclosed July 2026, reported by theviper17y.
Vulnerability Overview
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.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user.
CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Reaching this weakness in RPB Chessboard <= 8.1.2 takes no account at all. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.
Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For RPB Chessboard the fix is 8.1.3: builds <= 8.1.2 are affected, anything from 8.1.3 onward is not.
Remediation
Update to version 8.1.3, or a newer patched version
How does WordSec protect against this?
Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: RPB Chessboard 8.1.3 closes this, and updating the plugin is the step that ends it.
- Firewall
- Login Security
- Alerts
External References
Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C