CVE-2026-24352 identifies a session fixation vulnerability in PluXml CMS, specifically confirmed in versions 5.8.21 and 5.9.0-rc7. The issue arises because the CMS permits the session identifier (session ID) to be set prior to user authentication and does not regenerate or change this session ID upon successful login. This behavior violates secure session management best practices, as it allows an attacker to predetermine a session ID and trick a victim into authenticating with that session ID. Once the victim logs in, the attacker can use the fixed session ID to hijack the authenticated session, gaining unauthorized access to the victim’s account and potentially sensitive information. The vulnerability is classified under CWE-384 (Session Fixation). The CVSS v4.0 base score of 4.8 reflects a medium severity, with the attack vector being local (AV:L), requiring low attack complexity (AC:L), no privileges (PR:N), and user interaction (UI:P). The vulnerability impacts confidentiality and integrity with limited scope and no availability impact. The vendor was notified early but has not disclosed detailed affected version ranges or released patches. No known exploits have been reported in the wild, but the risk remains for organizations using the affected versions. Other versions of PluXml CMS have not been tested, so the vulnerability may be more widespread. This vulnerability highlights the importance of regenerating session IDs upon authentication to prevent session fixation attacks.

The primary impact of this vulnerability is unauthorized access to authenticated user sessions, which compromises confidentiality and integrity of user data and application state. Attackers can hijack sessions without needing user credentials, potentially leading to data theft, unauthorized actions, or privilege escalation within the CMS. This can undermine trust in the affected websites and lead to data breaches or defacement. Since PluXml CMS is used by various organizations for content management, any site relying on vulnerable versions is at risk of session hijacking attacks. The lack of patches and vendor response increases the window of exposure. Although the attack vector is local and requires user interaction, phishing or social engineering could be used to lure victims into using attacker-supplied session IDs. The impact is limited to confidentiality and integrity, with no direct availability impact. Organizations with sensitive or high-value content managed via PluXml CMS are particularly at risk.

1. Immediately upgrade PluXml CMS to a version that addresses this vulnerability once an official patch is released. 2. Until patches are available, implement server-side session management controls to forcibly regenerate session IDs upon successful authentication, ensuring old session IDs are invalidated. 3. Configure web application firewalls (WAFs) to detect and block suspicious session fixation attempts, such as session IDs supplied via URL parameters or cookies before login. 4. Educate users and administrators about the risks of session fixation and encourage cautious behavior regarding session identifiers, especially avoiding clicking on suspicious links. 5. Employ additional authentication mechanisms such as multi-factor authentication (MFA) to reduce the impact of session hijacking. 6. Monitor logs for unusual session activity or repeated session ID reuse patterns. 7. Review and harden session cookie attributes (e.g., HttpOnly, Secure, SameSite) to reduce session theft risks. 8. Conduct a thorough audit of all PluXml CMS instances to identify and remediate vulnerable versions. 9. Consider isolating critical CMS functions behind VPNs or IP whitelisting to reduce exposure. These measures go beyond generic advice by focusing on session regeneration, WAF tuning, and user education specific to session fixation.