CVE-2025-30668 is an integer underflow vulnerability (CWE-191) identified in Zoom Communications, Inc's Zoom Workplace Apps. An integer underflow occurs when an arithmetic operation causes a numeric value to wrap around below its minimum representable value, potentially leading to unexpected behavior or memory corruption. In this case, the flaw exists within certain versions of Zoom Workplace Apps and can be triggered by an authenticated user via network access. Exploiting this vulnerability allows the attacker to cause a denial of service (DoS) condition, disrupting the availability of the affected application. The vulnerability does not impact confidentiality or integrity directly but results in service unavailability. The CVSS 3.1 base score is 6.5 (medium severity), reflecting that the attack vector is network-based (AV:N), requires low attack complexity (AC:L), and requires privileges (PR:L) but no user interaction (UI:N). The scope remains unchanged (S:U), and the impact is limited to availability (A:H) without affecting confidentiality or integrity. No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability was reserved in March 2025 and published in May 2025, indicating recent discovery and disclosure. The lack of patches suggests organizations should prioritize monitoring and mitigation to prevent potential exploitation once exploit code becomes available.

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 workflow management. A successful denial of service attack could disrupt business operations, delay communications, and impact productivity, especially in organizations heavily reliant on Zoom's ecosystem. Sectors such as finance, healthcare, government, and critical infrastructure that depend on continuous availability of communication tools may experience operational setbacks. While the vulnerability does not compromise data confidentiality or integrity, the disruption of service can have cascading effects on business continuity and incident response capabilities. Additionally, organizations with compliance obligations around service availability and uptime (e.g., under GDPR or sector-specific regulations) may face regulatory scrutiny if disruptions occur. The requirement for authenticated access limits the attack surface to internal or trusted users, but insider threats or compromised credentials could be leveraged to exploit this vulnerability.

1. Monitor for official patches or updates from Zoom Communications and apply them promptly once available. 2. Implement strict access controls and multi-factor authentication (MFA) to reduce the risk of credential compromise and unauthorized authenticated access. 3. Employ network segmentation and limit access to Zoom Workplace Apps to only necessary users and devices. 4. Monitor application logs and network traffic for unusual activity that could indicate attempts to exploit this vulnerability or cause service disruptions. 5. Prepare incident response plans specifically addressing denial of service scenarios affecting collaboration tools. 6. Consider temporary compensating controls such as restricting the use of vulnerable app versions or disabling non-essential features that may trigger the underflow until patches are applied. 7. Educate users about the importance of safeguarding credentials to prevent insider exploitation. 8. Engage with Zoom support or security advisories to stay informed about emerging threats and remediation guidance.