A stored cross‑site scripting flaw allows an attacker to create a malicious portal preview link that runs arbitrary JavaScript with the permissions of any authenticated staff or member who opens it, potentially enabling account takeover. This is a classic reflected XSS weakness classified as CWE‑79, and it requires the victim to interact with the crafted link while being logged in. The impact is the execution of code in the context of the authenticated user, preserving the attacker’s privileges within the system.

Ghost CMS versions 5.43.0 through 5.12.04 and 6.0.0 through 6.14.0, along with Ghost Portal component versions 2.29.1 through 2.51.4 and 2.52.0 through 2.57.0, are vulnerable. For Ghost 5.x users, upgrading to v5.121.0 or later (which includes Portal v2.51.5) resolves the issue; for Ghost 6.x users, upgrading to v6.15.0 or later (which includes Portal v2.57.1) is required. Installations that use a custom or self‑hosted portal must rebuild or update the portal to the latest patched version.

The CVSS score of 8.8 indicates high severity, while the EPSS score of less than 1% reflects a low but not negligible likelihood of exploitation. The vulnerability is not listed in the CISA KEV catalog, so no confirmed public exploits are known. Attackers need an authenticated session and the victim must click the malicious link, but once executed the script runs with the victim's user rights, enabling further compromise of the account and potentially the broader platform.