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.
Exploitability
AV:NAC:LPR:NUI:NScope
S:CImpact
C:LI:LA:N7.2/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:NInjection