CVE-2022-40373 is a Cross Site Scripting (XSS) vulnerability identified in FeehiCMS version 2.1.1. This vulnerability allows remote attackers to execute arbitrary code by uploading a specially crafted XML file. The vulnerability stems from improper input validation and sanitization of XML content uploaded to the CMS, which then gets processed and rendered in a way that enables injection of malicious scripts. When a victim user accesses the affected content, the malicious script executes within their browser context, potentially leading to session hijacking, credential theft, or unauthorized actions performed on behalf of the user. The CVSS v3.1 base score is 5.4 (medium severity), with the vector indicating network attack vector (AV:N), low attack complexity (AC:L), requiring privileges (PR:L), user interaction (UI:R), scope changed (S:C), and low impact on confidentiality and integrity (C:L/I:L) but no impact on availability (A:N). The scope change suggests that the vulnerability affects resources beyond the initially vulnerable component, potentially impacting other parts of the system or users. Although no known exploits are reported in the wild, the vulnerability represents a credible risk, especially in environments where FeehiCMS is used to manage web content accessible by multiple users. FeehiCMS is an open-source content management system primarily used in Chinese-speaking regions but also deployed internationally in smaller or specialized web projects. The lack of vendor or product details in the CVE record limits precise identification of affected modules, but the vulnerability clearly involves XML file upload handling and XSS attack vectors (CWE-79).

For European organizations using FeehiCMS 2.1.1, this vulnerability could lead to unauthorized script execution within users' browsers, resulting in compromised user sessions, theft of sensitive information such as authentication tokens, and potential unauthorized actions performed with user privileges. This may affect the confidentiality and integrity of user data and web application functionality. Organizations relying on FeehiCMS for public-facing websites or intranet portals could face reputational damage, data breaches, and regulatory compliance issues (e.g., GDPR) if user data is exposed or manipulated. The requirement for user interaction (UI:R) means that successful exploitation depends on users visiting maliciously crafted pages or content, which could be facilitated by phishing or social engineering. The scope change (S:C) indicates that the vulnerability might allow attackers to affect components beyond the initial vulnerable module, potentially amplifying the impact. Although availability is not directly impacted, the indirect consequences of data compromise or trust erosion could disrupt business operations. Given the medium CVSS score and the nature of XSS attacks, the threat is significant but not critical, especially if mitigations and user awareness are in place.

Apply any available patches or updates from FeehiCMS developers as soon as they are released. Since no patch links are currently provided, monitor official FeehiCMS channels for updates addressing this vulnerability. Implement strict input validation and sanitization on all XML file uploads to ensure that any embedded scripts or malicious payloads are neutralized before processing or rendering. Configure web application firewalls (WAFs) with rules to detect and block suspicious XML payloads and common XSS attack patterns targeting FeehiCMS endpoints. Restrict privileges required to upload XML files to trusted users only, minimizing the risk of malicious uploads by unauthorized or low-privilege users. Educate users about the risks of interacting with untrusted content and encourage cautious behavior to reduce the likelihood of successful social engineering leading to exploitation. Conduct regular security assessments and penetration testing focused on XML handling and XSS vulnerabilities within FeehiCMS deployments. Implement Content Security Policy (CSP) headers to limit the execution of unauthorized scripts in the browser context, mitigating the impact of potential XSS attacks. Monitor logs and network traffic for unusual activity related to XML uploads or script execution attempts to enable early detection of exploitation attempts.