CVE-2026-42897

Microsoft Exchange Server Spoofing Vulnerability

CVSS 8.1 high · Microsoft Microsoft Exchange Server 2016 Cumulative Update 23 · published 2026-05-14

Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.

NVD · CVE.org

Coverage 2 sources

1. 2026-05-15 Help Net Security critical Unpatched Microsoft Exchange Server vulnerability exploited (CVE-2026-42897)

   Microsoft warns of actively exploited XSS vulnerability in on-premises Exchange Server (CVE-2026-42897)

2. 2026-05-15 CISA Cybersecurity Advisories critical CISA Adds One Known Exploited Vulnerability to Catalog

   CISA adds CVE-2026-42897 to its Known Exploited Vulnerabilities Catalog due to active exploitation.

3. 2026-07-30 Help Net Security high Laundry Bear’s new Microsoft Exchange attack triggers on email open (CVE-2026-42897)

   Laundry Bear exploits CVE-2026-42897 in Microsoft Exchange via email.

Also covered

• CVE-2026-86950 Apple iOS and iPadOS CVSS 8.8 · 1 article · 2026-09-29
• CVE-2023-6548 Cloud Software Group NetScaler ADC CVSS 5.5 · 1 article · 2026-09-28
• CVE-2023-25608 Fortinet FortiAP-W2 CVSS 5.2 · 1 article · 2026-09-28
• CVE-2026-88772 Memory overflow vulnerability leading to Remote Code Execution or Denial of Service CVSS 9.5 · 3 articles · 2026-09-28
• CVE-2026-88771 A remote code execution vulnerability exists due to improper input validation, which can allow an unauthenticated attacker to execute arbitrary commands CVSS 9.5 · 3 articles · 2026-09-28