CVE-2026-55057 is a vulnerability classified as CWE-190 (Integer Overflow or Wraparound) affecting Microsoft 365 Apps for Enterprise version 16.0.1. The issue allows an unauthorized attacker with local access to cause an integer overflow or wraparound condition, potentially leading to information disclosure. The vulnerability does not impact integrity or availability but has a high impact on confidentiality. Microsoft has published an official fix and manages remediation for this cloud service. No known exploits are reported in the wild at this time.

The vulnerability can lead to unauthorized local disclosure of information due to integer overflow or wraparound. It does not affect system integrity or availability. The CVSS score of 5.5 reflects a medium severity with high confidentiality impact but no integrity or availability impact.

An official fix is available from Microsoft. Since this is a cloud-hosted service, Microsoft manages the remediation server-side. Users and administrators should ensure their Microsoft 365 Apps for Enterprise environment is updated according to the vendor advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55057 to mitigate this vulnerability.