CVE-2025-59683 is a vulnerability classified under CWE-863 (Incorrect Authorization) affecting Pexip Infinity versions 15.0 through 38.0 prior to 38.1. The flaw resides in the Secure Scheduler for Exchange service, which is responsible for integrating Pexip's video conferencing scheduling with Microsoft Exchange calendars. Specifically, when used with Office 365 Legacy Exchange Tokens, the service improperly enforces access controls, allowing remote attackers to bypass authorization checks. This enables attackers to read potentially sensitive scheduling data, which could include meeting details and participant information. Additionally, attackers can exploit this weakness to excessively consume system resources, leading to denial of service conditions that degrade or disrupt service availability. The vulnerability is remotely exploitable without requiring authentication or user interaction, increasing its risk profile. The CVSS v3.1 base score is 8.2, reflecting high severity due to network attack vector, low attack complexity, no privileges required, and no user interaction needed. Although no public exploits have been reported yet, the vulnerability's characteristics suggest it could be weaponized in targeted attacks or automated scanning campaigns. The issue was reserved in September 2025 and published in December 2025, with no official patches linked in the provided data, but version 38.1 or later is implied to contain the fix. Organizations using Pexip Infinity integrated with Office 365, particularly those relying on legacy token mechanisms, should consider this vulnerability a critical security concern.

For European organizations, the impact of CVE-2025-59683 can be significant. Pexip Infinity is widely used for enterprise video conferencing and collaboration, often integrated with Microsoft Office 365 environments common across Europe. Exploitation could lead to unauthorized disclosure of sensitive meeting and scheduling information, potentially exposing confidential business discussions or personal data protected under GDPR. The denial of service aspect could disrupt critical communication infrastructure, affecting business continuity and operational efficiency. This is particularly impactful for sectors reliant on secure and reliable video conferencing, such as finance, healthcare, government, and education. The remote, unauthenticated nature of the vulnerability increases the risk of widespread exploitation, including by cybercriminals or state-sponsored actors targeting European enterprises. Resource exhaustion attacks could also degrade service availability, impacting remote work capabilities and collaboration. The combination of confidentiality loss and availability disruption elevates the threat to a high level, necessitating urgent remediation to protect sensitive data and maintain service reliability.

To mitigate CVE-2025-59683, European organizations should take the following specific actions: 1) Immediately upgrade Pexip Infinity to version 38.1 or later, where the vulnerability is addressed. 2) Review and disable the use of Office 365 Legacy Exchange Tokens in favor of modern, more secure authentication methods such as OAuth 2.0 where possible. 3) Implement strict access controls and network segmentation to limit exposure of the Secure Scheduler for Exchange service to trusted internal networks only. 4) Monitor system logs and resource usage metrics for unusual spikes indicative of exploitation attempts or denial of service conditions. 5) Conduct vulnerability scanning and penetration testing focused on Pexip Infinity deployments to identify potential exploitation vectors. 6) Educate IT and security teams about the risks associated with legacy token usage and improper authorization vulnerabilities. 7) Coordinate with Microsoft 365 administrators to ensure secure token management and minimize legacy token dependencies. 8) Apply network-level protections such as Web Application Firewalls (WAFs) with custom rules to detect and block suspicious requests targeting the scheduler service. These targeted measures go beyond generic patching and help reduce the attack surface and detect potential exploitation early.