Risk Letters

Exploited vulnerability

CVE-2026-42897

TLP:CLEAR

Microsoft Exchange Server Cross-Site Scripting 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.

Facts

  • Vendor: Microsoft
  • Product: Microsoft
  • CVSS: 8.1
  • EPSS (probability of exploitation within 30 days): 70.7 %
  • On CISA's Known Exploited Vulnerabilities list since: 15 May 2026
  • First known exploitation: 15 May 2026
  • CISA's deadline for US federal agencies: 29 May 2026
  • Weakness: CWE-79
  • First seen by Risk Letters: 15 May 2026

Members see which Nordic sectors the flaw hits, and what to do about it.

Get the full brief

Data: NVD (public domain), CISA KEV, FIRST EPSS, MITRE ATT&CK, AlienVault OTX. NVD