CVE-2022-42486 is a stored cross-site scripting (XSS) vulnerability identified in the User group management component of baserCMS, an open-source content management system widely used for website management. This vulnerability affects baserCMS versions prior to 4.7.2. The flaw allows a remote attacker who has authenticated administrative privileges to inject arbitrary malicious scripts into the application. Because the vulnerability is stored XSS, the injected script persists in the application and is served to other users who access the affected pages, potentially leading to session hijacking, privilege escalation, or other malicious activities. The attack requires the attacker to have administrative-level access, which limits the initial attack surface but increases the risk if an administrator account is compromised or misused. The CVSS v3.1 base score is 4.8 (medium severity), reflecting that the attack vector is network-based (AV:N), with low attack complexity (AC:L), but requires high privileges (PR:H) and user interaction (UI:R). The vulnerability impacts confidentiality and integrity but not availability. No known exploits are reported in the wild as of the published date (December 7, 2022). The vulnerability is classified under CWE-79, which covers improper neutralization of input leading to XSS. The absence of patch links suggests that users should upgrade to baserCMS version 4.7.2 or later, where the issue is resolved.

For European organizations using baserCMS, especially those managing websites with sensitive user data or internal administrative portals, this vulnerability poses a moderate risk. An attacker with administrative access could inject malicious scripts that execute in the browsers of other users, potentially stealing session cookies, redirecting users to phishing sites, or performing unauthorized actions on behalf of users. This can lead to data breaches, reputational damage, and regulatory non-compliance under GDPR if personal data is exposed. Since exploitation requires administrative privileges, the primary risk vector is compromised or malicious administrators or insiders. The vulnerability could also be leveraged in multi-tenant environments where baserCMS is used to manage multiple sites, increasing the scope of impact. Although no active exploitation is reported, the presence of this vulnerability in publicly accessible CMS platforms makes it a target for attackers seeking to escalate privileges or maintain persistence. The impact on confidentiality and integrity is significant in environments where administrative accounts are shared or weakly protected.

1. Immediate upgrade to baserCMS version 4.7.2 or later, where the vulnerability is patched, is the most effective mitigation. 2. Implement strict access controls and monitoring on administrative accounts to prevent unauthorized access. Use multi-factor authentication (MFA) for all administrative users to reduce the risk of credential compromise. 3. Conduct regular audits of user group management activities to detect any suspicious modifications or script injections. 4. Employ Content Security Policy (CSP) headers to restrict the execution of unauthorized scripts in browsers, mitigating the impact of potential XSS payloads. 5. Sanitize and validate all inputs in the user group management interface, even beyond the vendor patch, to ensure no residual injection vectors remain. 6. Educate administrators on phishing and social engineering risks to prevent credential theft. 7. Monitor web application logs for unusual activity patterns that could indicate exploitation attempts. 8. In environments where immediate upgrade is not feasible, consider temporary web application firewall (WAF) rules to detect and block suspicious script injection attempts targeting user group management endpoints.