CVE-2026-24778 is a cross-site scripting (XSS) vulnerability classified under CWE-79 affecting the TryGhost Ghost content management system and its Portal component. The flaw arises from improper neutralization of input during web page generation, allowing an attacker to inject malicious JavaScript code into crafted links. When an authenticated staff user or member clicks such a link, the injected script executes with their privileges, potentially enabling actions such as session hijacking, credential theft, or account takeover. The vulnerability affects Ghost versions 5.43.0 through 5.12.04 and 6.0.0 through 6.14.0, and Portal versions 2.29.1 through 2.51.4 and 2.52.0 through 2.57.0. Ghost automatically loads the latest Portal patch via CDN, but self-hosted or customized Portal instances require manual updates. The vulnerability does not require prior authentication but does require the victim to interact with the malicious link. The CVSS v3.1 score of 8.8 indicates a high-severity issue with network attack vector, low attack complexity, no privileges required, user interaction required, and high impact on confidentiality, integrity, and availability. No known exploits are currently reported in the wild, but the potential for account takeover makes this a critical risk for organizations relying on Ghost CMS for managing content and user memberships.

For European organizations, the impact of CVE-2026-24778 can be significant, especially for those using Ghost CMS to manage websites, blogs, or membership portals. Successful exploitation can lead to unauthorized execution of JavaScript in the context of authenticated users, enabling attackers to steal session tokens, escalate privileges, or perform actions on behalf of legitimate users. This can result in account takeover, data leakage, defacement, or further compromise of internal systems. Organizations handling sensitive or regulated data through Ghost portals may face compliance violations, reputational damage, and operational disruptions. Since Ghost is popular among media, publishing, and community platforms, the risk extends to sectors such as journalism, education, and non-profits across Europe. The automatic loading of Portal via CDN mitigates some risk for standard installations, but customized deployments remain vulnerable until manually patched. The requirement for user interaction means phishing or social engineering campaigns could be used to lure victims, increasing the threat surface. Overall, the vulnerability threatens confidentiality, integrity, and availability of web services relying on Ghost CMS within European digital infrastructure.

1. Upgrade Ghost CMS to version 5.121.0 or later if using the 5.x branch, or to 6.15.0 or later if using the 6.x branch, as these versions include patched Portal components. 2. For installations using customized or self-hosted Portal versions, manually update or rebuild the Portal component to the latest patched version (Portal v2.51.5 or v2.57.1 respectively). 3. Review and restrict user permissions to minimize the impact of compromised accounts, ensuring least privilege principles are enforced for staff and members. 4. Implement Content Security Policy (CSP) headers to limit the execution of unauthorized scripts and reduce XSS impact. 5. Educate users and staff about phishing risks and suspicious links to reduce the likelihood of user interaction with malicious URLs. 6. Monitor web server and application logs for unusual activity, including unexpected JavaScript execution or anomalous user behavior. 7. Consider deploying web application firewalls (WAF) with rules to detect and block XSS payloads targeting Ghost CMS endpoints. 8. Regularly audit and sanitize user-generated content inputs and outputs to prevent injection of malicious code. 9. Maintain an incident response plan to quickly isolate and remediate compromised accounts or systems if exploitation is suspected.