Piranha CMS Stored Cross-Site Scripting Vulnerability

A stored cross-site scripting vulnerability has been identified in Piranha CMS version 12.1, specifically within the Markdown content blocks of Standard Page and Standard Archive Page types. This vulnerability allows authenticated users to inject unsanitized JavaScript, which is then executed during page preview or public access, creating a persistent XSS risk.

Impact

Exploitation of this vulnerability allows for stored cross-site scripting, where injected scripts are executed in the context of the user viewing the page.

Reproduction

To reproduce this vulnerability, log into Piranha CMS as an authenticated user and navigate to the page manager. Create a new page of type Standard Page or Standard Archive Page. After saving the page, add a Markdown block and inject a script payload, such as an iframe or a details tag with an alert script. Save the changes and preview the page to see the injected script execute.

Remediation

Users are advised to update to Piranha CMS version 12.1 or later, where this vulnerability has been addressed.