CVE-2026-42897

What is affected

Vendor	Microsoft
Product	Microsoft
Weakness	CWE-79

The vulnerability

Microsoft Exchange Server contains a cross-site scripting vulnerability during web page generation in Outlook Web Access and when certain interaction conditions are met, arbitrary JavaScript can be executed in the browser context.

Required action

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

US federal civilian agencies were required to act by 29 May 2026 under BOD 22-01. The deadline is a compliance date, not a measure of severity — it says nothing about how dangerous the flaw is to anyone else.

Where this comes from

Every field on this page is taken from the CISA Known Exploited Vulnerabilities catalog, last synced 12 Nov 2026, 00:29. Nothing here is our own assessment. For the technical scoring, see the NVD record below.

NVD record ↗ CVE.org record ↗