CVE-2026-42897 · netVigilance record NV26-0108
Microsoft Exchange Server Cross-Site Scripting
past due
What to do
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 deadline 2026-05-29 · passed 3 months ago · applies to US federal civilian agencies; used elsewhere as a reference SLA
What happened
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.
Who is affected
Microsoft Microsoft. Affected version ranges are listed in the vendor advisory and the NVD entry linked under Sources.
Weakness class: CWE-79.
Timeline
- Added to CISA KEVExploitation in the wild confirmed by CISA
- CISA remediation deadlinepassed 3 months ago
Sources
- NVD entry for CVE-2026-42897 nvd.nist.gov/vuln/detail/CVE-2026-42897
- CISA Known Exploited Vulnerabilities catalog www.cisa.gov/known-exploited-vulnerabilities-catalog
- msrc.microsoft.com msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2026-42897
- learn.microsoft.com learn.microsoft.com/en-us/exchange/plan-and-deploy/post-installation-tasks/security-best-practices/exchange-emergency-mitigation-service
- nvd.nist.gov nvd.nist.gov/vuln/detail/CVE-2026-42897