CVE-2025-47275 is a critical improper authentication vulnerability (CWE-287) affecting the Auth0-PHP SDK versions starting from 8.0.0-BETA1 up to but not including 8.14.0. Auth0-PHP is a widely used PHP SDK that facilitates integration with Auth0's Authentication and Management APIs, enabling developers to implement authentication and authorization in PHP applications. The vulnerability specifically arises when applications use the Auth0-PHP SDK configured with CookieStore for session storage. In this configuration, session cookies include authentication tags that are susceptible to brute force attacks. An attacker can exploit this weakness by systematically guessing or brute forcing the authentication tags on session cookies, potentially allowing unauthorized access to user sessions without needing any prior authentication or user interaction. This flaw compromises the integrity and confidentiality of user sessions, enabling attackers to impersonate legitimate users and gain unauthorized access to protected resources. The vulnerability also affects other SDKs that rely on Auth0-PHP, including Auth0/symfony, Auth0/laravel-auth0, and Auth0/wordpress, if they use CookieStore for session management. The recommended remediation is to upgrade the Auth0/Auth0-PHP SDK to version 8.14.0 or later, where the issue has been patched. Additionally, rotating cookie encryption keys is advised as a precaution to invalidate any previously issued session cookies, which will be rejected after the upgrade. This vulnerability has a CVSS v3.1 base score of 9.1, indicating critical severity, with an attack vector of network, low attack complexity, no privileges required, and no user interaction needed. Although no known exploits are currently reported in the wild, the ease of exploitation and high impact make this a significant threat for applications relying on the vulnerable SDK versions.

For European organizations, this vulnerability poses a substantial risk to the security of web applications that utilize the Auth0-PHP SDK or its dependent SDKs with CookieStore session management. Successful exploitation can lead to unauthorized access to user accounts, potentially exposing sensitive personal data protected under GDPR, leading to regulatory penalties and reputational damage. The compromise of authentication tokens undermines trust in identity and access management systems, which are critical for sectors such as finance, healthcare, government, and e-commerce prevalent across Europe. Attackers could impersonate legitimate users, escalate privileges, or access confidential business information, causing operational disruptions and financial losses. Given the widespread adoption of Auth0 as an identity provider and the popularity of PHP-based web applications in Europe, the vulnerability could affect a broad range of organizations. Moreover, the lack of required authentication or user interaction for exploitation increases the likelihood of automated attacks targeting vulnerable endpoints. The need to rotate encryption keys and invalidate existing sessions may also impact user experience and require coordinated incident response efforts.

European organizations should immediately assess their use of the Auth0-PHP SDK and related SDKs to determine if they are running vulnerable versions (>= 8.0.0-BETA1 and < 8.14.0) with CookieStore session storage. The primary mitigation is to upgrade to Auth0-PHP SDK version 8.14.0 or later, which contains the patch for this vulnerability. Following the upgrade, organizations must rotate cookie encryption keys to invalidate all existing session cookies, preventing attackers from leveraging previously issued tokens. This key rotation should be planned carefully to minimize user disruption, potentially by informing users of forced re-authentication. Additionally, organizations should review their session management policies to ensure robust cryptographic protections and consider implementing additional layers of security such as multi-factor authentication (MFA) to reduce the impact of compromised sessions. Monitoring for unusual authentication patterns and brute force attempts on session cookies is recommended to detect exploitation attempts early. Finally, developers should audit their applications to avoid reliance on vulnerable SDK versions and ensure secure configuration of session storage mechanisms.