CVE-2025-45769 identifies a high-severity vulnerability in the php-jwt library version 6.11.0, specifically related to weak encryption mechanisms. The php-jwt library is widely used in PHP applications to handle JSON Web Tokens (JWT), which are critical for authentication and authorization processes in web services. Weak encryption in this context implies that the cryptographic algorithms or key management practices employed by the library do not provide sufficient protection against cryptanalysis or brute-force attacks. This vulnerability is classified under CWE-326, which refers to the use of weak cryptographic primitives. The CVSS v3.1 base score of 7.3 indicates a high severity, with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L showing that the vulnerability can be exploited remotely over the network without any privileges or user interaction, and it impacts confidentiality, integrity, and availability to a low degree each. Although no known exploits are currently reported in the wild, the weakness in encryption could allow attackers to forge or tamper with JWT tokens, potentially leading to unauthorized access, privilege escalation, or denial of service by invalidating tokens or causing application errors. The lack of patch links suggests that a fix may not yet be publicly available, emphasizing the need for immediate attention from developers and security teams using this library.

For European organizations, the impact of this vulnerability can be significant, especially for those relying on php-jwt for securing web applications, APIs, and microservices. Exploitation could lead to unauthorized access to sensitive data or systems, undermining user authentication and session management. This can result in data breaches, loss of customer trust, regulatory non-compliance (e.g., GDPR violations), and potential financial penalties. The integrity and availability impacts, although rated low individually, collectively pose risks such as token forgery or denial of service conditions that disrupt business operations. Organizations in sectors like finance, healthcare, e-commerce, and government, which often use JWT for secure communications, are particularly vulnerable. The remote and unauthenticated nature of the exploit increases the risk profile, as attackers do not need insider access or user interaction to attempt exploitation.

Immediate mitigation steps include auditing all applications and services that utilize php-jwt version 6.11.0 to identify exposure. Organizations should monitor vendor announcements for patches or updates addressing this vulnerability and prioritize applying them once available. In the interim, consider implementing compensating controls such as enforcing additional layers of authentication, using short-lived tokens to reduce the window of exploitation, and employing web application firewalls (WAFs) to detect and block suspicious JWT manipulation attempts. Developers should review cryptographic configurations and consider migrating to more secure JWT libraries or versions that use robust encryption algorithms and key management practices. Additionally, conducting thorough code reviews and penetration testing focused on authentication mechanisms can help identify and remediate related weaknesses. Logging and monitoring JWT validation failures can provide early detection of exploitation attempts.