CVE-2026-70105: CWE-20: Improper Input Validation in Microsoft Microsoft 365 Apps for Enterprise

This vulnerability involves improper input validation in Microsoft Office Word, part of Microsoft 365 Apps for Enterprise, which could allow an unauthorized attacker to disclose information over a network. The CVSS 3.1 base score is 6.5, indicating a medium severity issue with network attack vector, low attack complexity, no privileges required, and user interaction required. The vulnerability affects multiple versions including =16.0.1, =19.0.0, >=1.0.0 <16.112.26081010, =16.0.0, >=16.0.1 <16.112.26081010, >=16.0.0 <16.112.26081010, and >=16.0.1 <16.0.5565.1000. Microsoft has issued an official fix and manages remediation for this cloud service. No active exploitation has been reported.

An attacker exploiting this vulnerability could disclose sensitive information over a network without requiring privileges but with user interaction. The impact is limited to confidentiality loss; integrity and availability are not affected. The medium severity reflects the moderate risk of information disclosure.

An official fix is available from Microsoft. Since this is a cloud-hosted service, Microsoft manages remediation server-side. Users and administrators should apply the official updates as provided in the Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-70105 to mitigate this vulnerability.