8.1High KEV

CVE-2026-42897Microsoft Exchange Server Spoofing Vulnerability

Microsoft Microsoft Exchange Server 2016 Cumulative Update 23; Microsoft Microsoft Exchange Server 2019 Cumulative Update 14; Microsoft Microsoft Exchange Serv… Published: (6 months ago)

Known exploited — Microsoft Exchange Server Cross-Site Scripting Vulnerability

CISA confirmed this vulnerability is used in real attacks on 15.05.2026. Remediation deadline for US federal agencies: 29.05.2026.

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. https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-42897 ; https://learn.microsoft.com/en-us/exchange/plan-and-deploy/post-installation-tasks/security-best-practices/exchange-emergency-mitigation-service ; https://nvd.nist.gov/vuln/detail/CVE-2026-42897

Description

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.

Weakness (CWE): CWE-79

Data: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Published as the sources state it, in English.

Affected products and versions

VendorProductVersions
microsoft exchange server 2016
microsoft exchange server 2016 15.01.0.0 – < 15.01.2507.069
microsoft exchange server 2019 15.02.0.0 – < 15.02.1544.041
microsoft exchange server se 15.02.0.0 – < 15.02.2562.043
microsoft exchange server subscription edition < 15.02.2562.043
Microsoft Microsoft Exchange Server 2016 Cumulative Update 23 15.01.0.0 – < 15.01.2507.069
Microsoft Microsoft Exchange Server 2019 Cumulative Update 14 15.02.0.0 – < 15.02.1544.041
Microsoft Microsoft Exchange Server 2019 Cumulative Update 15 15.02.0.0 – < 15.02.1748.046
Microsoft Microsoft Exchange Server Subscription Edition RTM 15.02.0.0 – < 15.02.2562.043

References and patches

CPE matches (NVD) (40)

  • cpe:2.3:a:microsoft:exchange_server:2016:-:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_1:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_10:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_11:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_12:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_13:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_14:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_15:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_16:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_17:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_18:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_19:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_2:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_20:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_21:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_22:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_23:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_3:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_4:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_5:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_6:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_7:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_8:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_9:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2019:-:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_1:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_10:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_11:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_12:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_13:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_14:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_2:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_3:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_4:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_5:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_6:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_7:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_8:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_9:*:*:*:*:*:*
  • cpe:2.3:a:microsoft:exchange_server_subscription_edition:*:*:*:*:*:*:*:* < 15.02.2562.043