CVE-2025-29573 is a Cross-Site Scripting (XSS) vulnerability identified in Mezzanine CMS version 6.0.0, specifically within the "View Entries" feature of the Forms module. XSS vulnerabilities occur when an application includes untrusted data in a web page without proper validation or escaping, allowing attackers to inject malicious scripts that execute in the context of the victim's browser. This particular vulnerability is classified under CWE-79, which covers improper neutralization of input during web page generation. The CVSS 3.1 base score is 6.1 (medium severity), with vector AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N, indicating that the attack can be performed remotely over the network without privileges, requires low attack complexity, no privileges, but does require user interaction (the victim must visit a crafted page). The scope is changed (S:C), meaning the vulnerability affects resources beyond the initially vulnerable component. The impact affects confidentiality and integrity to a low degree, with no impact on availability. Although no known exploits are currently reported in the wild, the vulnerability could be leveraged by attackers to steal session cookies, perform actions on behalf of users, or conduct phishing attacks by injecting malicious scripts into the CMS interface. Mezzanine CMS is a Python-based content management system used by various organizations for website management, and the Forms module is commonly used for collecting user input, making this vulnerability a potential vector for targeted attacks against website administrators or users interacting with the CMS forms.

For European organizations using Mezzanine CMS 6.0.0, this XSS vulnerability poses a risk primarily to the confidentiality and integrity of data handled through the Forms module. Attackers exploiting this flaw could hijack user sessions, steal sensitive information, or manipulate form data, potentially leading to unauthorized access or data leakage. Given the scope change, the vulnerability could allow attackers to affect other components or users beyond the initially targeted module, increasing the risk of broader compromise. Organizations in sectors such as government, education, and SMEs that rely on Mezzanine CMS for public-facing websites or internal portals could face reputational damage, regulatory scrutiny under GDPR for data breaches, and operational disruptions if attackers leverage the vulnerability for phishing or social engineering campaigns. The requirement for user interaction means that phishing or social engineering tactics may be used to lure victims into triggering the exploit, emphasizing the need for user awareness and technical controls.

To mitigate this vulnerability, European organizations should prioritize upgrading Mezzanine CMS to a patched version once available from the vendor or community. In the absence of an official patch, organizations can implement input validation and output encoding on all user-supplied data within the Forms module to neutralize malicious scripts. Employing Content Security Policy (CSP) headers can reduce the impact of XSS by restricting the execution of unauthorized scripts. Web Application Firewalls (WAFs) configured to detect and block XSS payloads targeting the Forms module can provide interim protection. Additionally, organizations should conduct security awareness training to educate users about the risks of clicking on suspicious links or submitting untrusted content. Regular security audits and penetration testing focused on web application vulnerabilities can help identify and remediate similar issues proactively. Monitoring logs for unusual activity related to the Forms module may also help detect exploitation attempts early.