CVE-2026-42897
high
KEV
CVSS v3
8.1
CVSS v4 NEW
—
VIR risk
9.6
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.
CISA KEV
- Vendor
- Microsoft
- Product
- Microsoft
- Due date
- 2026-05-29
Predictions
Exploit likelihood
99%
Patch ETA
—
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Mitigation details
Source: Microsoft Security Response Center · View original ↗ · proprietary-no-redistribution
Full prose not cached — VIR stores only structured fields (affected/fixed versions, references) for this source. Click "View original" above for the vendor's full advisory.
Affected
| Vendor | Product | Version |
|---|---|---|
| microsoft | Windows Server 2012 | |
| microsoft | Windows Server 2012 (Server Core installation) | |
| microsoft | Windows Server 2012 R2 | |
| microsoft | Windows Server 2012 R2 (Server Core installation) | |
| microsoft | Microsoft Excel 2016 (32-bit edition) | |
| microsoft | Microsoft Excel 2016 (64-bit edition) | |
| microsoft | Microsoft Word 2016 (32-bit edition) | |
| microsoft | Microsoft Word 2016 (64-bit edition) | |
| microsoft | Microsoft Office 2016 (32-bit edition) | |
| microsoft | Microsoft Office 2016 (64-bit edition) | |
| microsoft | Windows Server 2016 | |
| microsoft | Office Online Server | |
| microsoft | Windows 10 Version 1607 for 32-bit Systems | |
| microsoft | Windows 10 Version 1607 for x64-based Systems | |
| microsoft | Windows Server 2016 (Server Core installation) | |
| microsoft | Microsoft SharePoint Enterprise Server 2016 | |
| microsoft | Microsoft SQL Server 2017 for x64-based Systems (GDR) | |
| microsoft | Windows 10 Version 1809 for 32-bit Systems | |
| microsoft | Windows 10 Version 1809 for x64-based Systems | |
| microsoft | Windows Server 2019 | |
| microsoft | Windows Server 2019 (Server Core installation) | |
| microsoft | Microsoft Office 2019 for 32-bit editions | |
| microsoft | Microsoft Office 2019 for 64-bit editions | |
| microsoft | Microsoft SharePoint Server 2019 | |
| microsoft | Visual Studio Code | |
| microsoft | Windows Admin Center | |
| microsoft | Microsoft .NET Framework 4.8 on Windows Server 2012 | |
| microsoft | Microsoft .NET Framework 4.8 on Windows Server 2012 R2 | |
| microsoft | Microsoft .NET Framework 4.8 on Windows Server 2016 | |
| microsoft | Microsoft .NET Framework 4.8 on Windows 10 Version 1607 for x64-based Systems | |
Exploits
Public proof-of-concept code below. AS-IS, for defenders and authorised testing only.
OS impact
Windows Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Application impact
| Vendor | Product | Versions | Fixed |
|---|---|---|---|
| microsoft | exchange_server | - | |
| microsoft | exchange_server | 2016 | |
| microsoft | exchange_server | 2019 | |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42897
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-42897
- 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
CWEs
CWE-79
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.