CVE-2025-30668 is a medium-severity vulnerability identified in Zoom Communications, Inc's Zoom Workplace Apps. The underlying issue is an integer underflow that leads to a NULL pointer dereference (CWE-476). This flaw can be triggered by an authenticated user through network access, resulting in a denial of service (DoS) condition. Specifically, the integer underflow causes the application to dereference a NULL pointer, which typically leads to application crashes or unexpected termination of the affected Zoom Workplace App processes. Since the vulnerability requires authentication and no user interaction beyond that, an attacker with valid credentials could exploit this flaw remotely to disrupt service availability. The CVSS 3.1 base score is 6.5, reflecting a medium severity level, with the vector indicating network attack vector (AV:N), low attack complexity (AC:L), privileges required (PR:L), no user interaction (UI:N), unchanged scope (S:U), no impact on confidentiality or integrity (C:N/I:N), but high impact on availability (A:H). No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability affects unspecified versions of Zoom Workplace Apps, and the issue was publicly disclosed on May 14, 2025. The integer underflow and NULL pointer dereference are common programming errors that can be mitigated with proper input validation and bounds checking.

For European organizations, this vulnerability poses a risk primarily to the availability of Zoom Workplace Apps, which are widely used for internal communications, collaboration, and remote work. A successful denial of service attack could disrupt business operations, causing meeting interruptions, loss of productivity, and potential cascading effects on dependent workflows. Organizations relying heavily on Zoom Workplace Apps for critical communications may face operational delays and increased support costs. Although the vulnerability does not compromise confidentiality or integrity, the availability impact could be significant, especially in sectors where continuous communication is vital, such as finance, healthcare, and government. Additionally, since exploitation requires authentication, insider threats or compromised credentials could be leveraged to trigger the DoS, increasing the risk profile. The lack of known exploits in the wild provides some temporary relief, but organizations should not be complacent given the potential for future exploitation.

European organizations should prioritize the following mitigations: 1) Monitor Zoom Communications' official channels for patches or updates addressing CVE-2025-30668 and apply them promptly once available. 2) Enforce strict access controls and multi-factor authentication (MFA) to reduce the risk of credential compromise, thereby limiting the pool of potential attackers who can exploit this vulnerability. 3) Implement network segmentation and monitoring to detect unusual activity from authenticated users that could indicate exploitation attempts. 4) Conduct internal audits of user privileges to ensure least privilege principles are followed, minimizing the number of users with access to vulnerable Zoom Workplace Apps. 5) Prepare incident response plans specifically for denial of service scenarios affecting communication platforms to reduce downtime impact. 6) Consider temporary alternative communication tools or backup solutions to maintain business continuity if Zoom Workplace Apps become unavailable due to exploitation. 7) Educate users about the importance of safeguarding credentials and recognizing suspicious activity to prevent insider exploitation.