A spoofing vulnerability exists in Microsoft Exchange Server when Outlook Web App (OWA) fails to properly handle web requests. An attacker who successfully exploited the vulnerability could perform script or content injection attacks, and attempt to trick the user into disclosing sensitive information. An attacker could also redirect the user to a malicious website that could spoof content or the vulnerability could be used as a pivot to chain an attack with other vulnerabilities in web services.
To exploit the vulnerability, an attacker could send a specially crafted email containing a malicious link to a user. An attacker could also use a chat client to social engineer a user into clicking the malicious link. However, in both examples the user must click the malicious link.
The security update addresses the vulnerability by correcting how OWA validates web requests.
## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Microsoft | Microsoft Exchange Server 2010 Service Pack 3 | | [KB4491413](https://patchblox.com/security/data/fix/microsoft/kb4491413.md) | Apr 9, 2019 | | Microsoft | Microsoft Exchange Server 2013 Cumulative Update 22 | | [KB4487563](https://patchblox.com/security/data/fix/microsoft/kb4487563.md) | Apr 9, 2019 | | Microsoft | Microsoft Exchange Server 2016 Cumulative Update 11 | | [KB4487563](https://patchblox.com/security/data/fix/microsoft/kb4487563.md) | Apr 9, 2019 | | Microsoft | Microsoft Exchange Server 2016 Cumulative Update 12 | | [KB4487563](https://patchblox.com/security/data/fix/microsoft/kb4487563.md) | Apr 9, 2019 | | Microsoft | Microsoft Exchange Server 2019 | | [KB4487563](https://patchblox.com/security/data/fix/microsoft/kb4487563.md) | Apr 9, 2019 | | Microsoft | Microsoft Exchange Server 2019 Cumulative Update 1 | | [KB4487563](https://patchblox.com/security/data/fix/microsoft/kb4487563.md) | Apr 9, 2019 | --- Data as of 2026-11-07T18:46:35Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.