cve 2026 55126

This tag covers CVE 2026 55126, a cross-site scripting vulnerability affecting supported on-premises editions of Microsoft SharePoint Server. The issue can allow an authenticated user to spoof content and potentially capture sensitive information. Microsoft addressed it in the July 14, 2026 security updates, including KB5002891, for SharePoint Server 2016, SharePoint Server 2019, and SharePoint Server Subscription Edition. The vulnerability is rated Important and has a CVSS 3.1 base score of 7.3. The available advisory reported no known exploitation at publication, while emphasizing the need for administrators to apply the applicable fixes across affected SharePoint deployments promptly.