CVE-2024-52947 is a cross-site scripting (XSS) vulnerability identified in LemonLDAP::NG, an open-source web single sign-on (SSO) and access management system widely used in various organizations for centralized authentication. The vulnerability exists in versions prior to 2.20.1 and specifically affects the 'upgrade session confirmation' page, which is part of the 'Upgrade session' plugin functionality. This plugin, when enabled by an administrator, allows users to extend their session duration. The flaw arises from insufficient sanitization of the 'url' parameter on this page, enabling remote attackers to inject arbitrary JavaScript or HTML code. Successful exploitation requires that the attacker has some level of privileges (PR:L) and that the victim performs an action (user interaction) such as clicking a crafted link. The vulnerability has a CVSS 3.1 base score of 6.1, reflecting a medium severity level, with impacts primarily on confidentiality and integrity due to potential session hijacking, credential theft, or unauthorized actions performed in the context of the victim's session. The scope is considered changed (S:C) because the vulnerability can affect other components or users beyond the initially compromised session. There are no known public exploits or patches available at the time of publication, emphasizing the need for administrators to apply updates promptly once released. The CWE classification is CWE-79, which corresponds to improper neutralization of input during web page generation, a common vector for XSS attacks. Given LemonLDAP::NG's role in authentication workflows, exploitation could facilitate further attacks such as privilege escalation or lateral movement within affected networks.

For European organizations, the impact of CVE-2024-52947 can be significant, especially for those relying on LemonLDAP::NG for critical authentication and access control services. Successful exploitation could lead to the compromise of user sessions, allowing attackers to impersonate legitimate users, steal sensitive information, or perform unauthorized actions within protected applications. This undermines confidentiality and integrity of user data and authentication processes. While availability is not directly impacted, the breach of trust and potential data leakage could have regulatory and reputational consequences, particularly under GDPR requirements. Organizations in sectors such as government, finance, healthcare, and telecommunications that use LemonLDAP::NG for SSO are at heightened risk. The requirement for some privilege and user interaction limits the attack surface but does not eliminate risk, especially in environments with large user bases or where phishing campaigns could be used to trigger the vulnerability. The absence of known exploits currently provides a window for proactive defense, but the medium severity score indicates that timely remediation is essential to prevent escalation.

Administrators should immediately verify whether the 'Upgrade session' plugin is enabled in their LemonLDAP::NG deployments and assess exposure of the upgrade session confirmation page. Until patches are available, consider disabling the 'Upgrade session' plugin if it is not essential to reduce attack surface. Implement strict input validation and output encoding on the 'url' parameter to prevent injection of malicious scripts. Employ Content Security Policy (CSP) headers to restrict execution of unauthorized scripts in browsers. Conduct user awareness training to mitigate risks from phishing or social engineering that could trigger user interaction. Monitor web server logs for suspicious requests targeting the 'url' parameter or unusual session upgrade attempts. Plan and prioritize upgrading to LemonLDAP::NG version 2.20.1 or later once the patch is released. Additionally, review and tighten administrative privileges to limit who can enable potentially risky plugins. Deploy web application firewalls (WAF) with rules to detect and block XSS payloads targeting this vulnerability. Finally, integrate vulnerability scanning and penetration testing focused on authentication components to detect similar issues proactively.