CVE-2026-24352 in PluXml
Summary
by MITRE • 02/27/2026
PluXml CMS allows a user's session identifier to be set before authentication. The value of this session ID stays the same after authentication. This behaviour enables an attacker to fix a session ID for a victim and later hijack the authenticated session.
The vendor was notified early about this vulnerability, but didn't respond with the details of vulnerability or vulnerable version range. Only versions 5.8.21 and 5.9.0-rc7 were tested and confirmed as vulnerable, other versions were not tested and might also be vulnerable.
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Analysis
by VulDB Data Team • 05/20/2026
This vulnerability in PluXml CMS represents a critical session management flaw that directly undermines the security of user authentication mechanisms. The core issue lies in the improper handling of session identifiers where the system allows a user's session ID to be established prior to successful authentication. This behavior creates a fundamental weakness in the authentication flow, as the session identifier remains static regardless of whether the user has been properly authenticated. The vulnerability enables attackers to manipulate session identifiers before authentication occurs, effectively allowing them to predict and fix session IDs that can later be used to hijack authenticated sessions. This flaw directly violates established security principles for session management and authentication handling, creating a pathway for unauthorized access to user accounts.
The technical implementation of this vulnerability stems from a failure in session initialization logic within the CMS authentication system. When a user begins the authentication process, the system generates a session identifier before verifying the user's credentials. This premature session creation means that an attacker who can observe or predict the session generation process can establish a fixed session ID that will remain unchanged even after successful authentication. The static nature of the session identifier post-authentication creates a persistent attack vector that can be exploited through session fixation techniques. This issue aligns with CWE-384, which specifically addresses session fixation vulnerabilities where the application fails to invalidate session identifiers upon authentication. The vulnerability also maps to ATT&CK technique T1563.002, which covers "T1563.002 - Credentials in Files" and related session manipulation tactics, as attackers can leverage this weakness to maintain persistent access to authenticated sessions.
The operational impact of this vulnerability extends beyond simple session hijacking to encompass broader security implications for PluXml installations. Attackers can exploit this weakness to gain unauthorized access to user accounts, potentially leading to data breaches, content manipulation, and privilege escalation within the CMS environment. The vulnerability affects the integrity and confidentiality of user sessions, as it allows attackers to impersonate authenticated users without requiring valid credentials. This creates a significant risk for content management systems where users may have administrative privileges, potentially enabling attackers to modify website content, delete files, or compromise the entire CMS infrastructure. The static session identifier also makes automated exploitation more feasible, as attackers can script the session fixation process rather than relying on manual observation and timing.
Mitigation strategies for this vulnerability must address the fundamental session management flaw in the PluXml CMS codebase. The primary recommendation involves implementing proper session invalidation and regeneration upon successful authentication, ensuring that session identifiers change dynamically when users transition from anonymous to authenticated states. Security patches should enforce that session identifiers are generated only after successful authentication, eliminating the window where attackers can manipulate session IDs before credential verification. Organizations should also implement session timeout mechanisms and regularly rotate session identifiers to minimize the window of opportunity for exploitation. Additionally, network-level protections such as secure session cookie attributes, proper HTTP headers, and monitoring for unusual session activity patterns can help detect and prevent exploitation attempts. The vendor should be urged to provide comprehensive patching guidance and vulnerability confirmation for affected versions, with thorough testing across all supported releases to identify potential similar issues in the codebase.