CVE-2026-42897Microsoft Exchange Server Cross-Site Scripting Vulnerability
CISA Known Exploited Vulnerabilities Data
Description
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.
CISA Due Date
May 29, 2026 (federal agency requirement)
Known Ransomware Campaign Use
Unknown
Notes
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
External References
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Data sourced from the CISA Known Exploited Vulnerabilities catalog. CISA does not endorse any commercial product or service.