Information disclosure in Microsoft products - CVE-2026-21260

Vulnerability identifier: #VU122586

CSH Severity: Medium

CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green

CVE-ID: CVE-2026-21260

CWE-ID: CWE-200

Exploitation vector: Remote access

Exploit availability: No public exploit available

Vendor: Microsoft

Affected software:
Microsoft SharePoint Server
Microsoft SharePoint Server Subscription Edition
Microsoft SharePoint Enterprise Server
Microsoft Office
Microsoft Outlook
Microsoft 365 Apps for Enterprise
Microsoft Office LTSC

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to excessive data output by the application in Microsoft Outlook. A remote attacker can use a specially crafted email and gain unauthorized access to sensitive information on the system.

Install updates from vendor's website.

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21260