CVE-2026-92227 in Extension
Summary
by MITRE • 09/29/2026
Joomla! Core - [20260914] - Core - MFA Authentication Bypass through rememberme cookies in Joomla 4.0.0-5.4.8, 6.0.0-6.1.3 - The premature issuance of an rememberme cookie leads to a MFA bypass vulnerability.
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Analysis
by VulDB Data Team • 09/29/2026
The identified vulnerability represents a critical authentication flaw within the core Multi-Factor Authentication (MFA) implementation of Joomla inadvertently creates a pathway for attackers to bypass the second factor entirely.
From a technical perspective, this vulnerability exploits the race condition and state management inconsistencies inherent in how session tokens are persisted across requests. When a user initiates login with valid primary credentials but has not yet completed the MFA step, the system incorrectly flags the authentication as sufficient enough to generate a long-lived rememberme cookie. This token is then stored on the client side and sent back with subsequent HTTP requests. Because the server trusts this cookie as proof of full authentication status without re-evaluating the completion of the secondary factor, an attacker who obtains or predicts such a cookie can authenticate as that user indefinitely. This mechanism effectively neutralizes the security benefit provided by MFA, reducing it to a single-factor authentication model for any session established via these improperly issued cookies.
The operational impact of this vulnerability is severe, particularly in environments where Joomla! serves administrative functions or handles sensitive data. An attacker with access to network traffic or compromised client devices can exploit this flaw to gain unauthorized administrative privileges without needing the user's MFA secret key or device. This bypass undermines the primary defense against credential stuffing and phishing attacks, as even strong passwords combined with proper MFA usage become ineffective if the session token is issued prematurely. The risk is exacerbated by the fact that rememberme cookies are designed for long-term persistence, meaning a single exploitation can lead to prolonged unauthorized access unless the cookie is manually cleared or rotated through specific administrative actions.
This vulnerability aligns closely with CWE-287, which describes Improper Authentication, specifically regarding the failure to properly validate authentication credentials before granting persistent session tokens. It also maps to MITRE ATT&CK technique T1078, Valid Accounts, as it allows attackers to maintain access using legitimate but improperly authenticated sessions. Furthermore, the mechanism relates to CWE-613, Insufficient Session Expiration, due to the long-lived nature of the compromised rememberme cookies which remain valid until explicitly invalidated or expired by external means rather than proper session lifecycle management protocols.
Mitigation strategies must focus on immediate patching and architectural review. The primary remediation is to upgrade Joomla! to a version that includes the corrected authentication logic where the issuance of persistent tokens is strictly gated behind successful completion of all required MFA steps. Administrators should also enforce strict cookie policies, ensuring that rememberme cookies are only set after explicit user consent following full multi-factor verification. Additionally, implementing short session timeouts and requiring periodic re-authentication for sensitive operations can reduce the window of opportunity for exploitation. Security teams should monitor access logs for unusual patterns indicative of MFA bypass attempts, such as successful logins from new geographic locations or devices that do not correspond with expected user behavior, although detection may be challenging given the legitimate appearance of the session tokens generated by this flaw.