CVE-2026-40332: Masa CMS open redirect via improper handling of scheme-relative URLs

Masa CMS is affected by an Open Redirect vulnerability due to improper handling of scheme-relative URLs. The application incorrectly interprets paths beginning with double slashes (//) as internal paths, failing to validate the redirect target before processing. The application treats these values as internal paths and processes them without confirming that the redirect target remains on the local site.

An attacker can craft a URL on the trusted Masa CMS domain that redirects a victim to an external attacker-controlled site. This can be used for phishing and, in some authentication flows, may expose tokens or other sensitive data to the external site. This issue has been fixed in versions 7.2.10, 7.3.15, 7.4.10, and 7.5.3. As a workaround, reject or rewrite redirect parameters that begin with // and consider disabling forceDirectoryStructure if compatible with the deployment.