CVE-2026-88204: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in Microsoft Microsoft SharePoint Server Subscription Edition

This vulnerability (CVE-2026-88204) in Microsoft SharePoint Server Subscription Edition is classified as CWE-79, indicating improper neutralization of input during web page generation leading to cross-site scripting. An authorized attacker can exploit this flaw to conduct spoofing attacks over a network. The CVSS 3.1 base score is 7.3 (high), reflecting network attack vector, low attack complexity, required privileges, user interaction, and high impact on confidentiality and integrity. The vulnerability affects versions >=16.0.0 and <16.0.20326.20190. Microsoft has published an official fix for this issue.

Successful exploitation can lead to high impact on confidentiality and integrity by enabling spoofing attacks via cross-site scripting. This could allow an attacker with authorized access to execute malicious scripts in the context of the affected SharePoint server, potentially compromising sensitive information or user sessions. Availability impact is not affected.

An official fix is available from Microsoft. Users should apply the security update provided in the Microsoft advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-88204 to remediate this vulnerability. No additional mitigation steps are indicated by the vendor advisory.