An elevation of privilege vulnerability exists when Microsoft Exchange Outlook Web Access (OWA) fails to properly handle web requests. An attacker who successfully exploited this vulnerability could perform script/content injection attacks and attempt to trick the user into disclosing sensitive information.
To exploit the vulnerability, an attacker could send a specially crafted email message containing a malicious link to a user. Alternatively, an attacker could use a chat client to social engineer a user into clicking the malicious link.
The security update addresses the vulnerability by correcting how Microsoft Exchange validates web requests.
Note: In order to exploit this vulnerability, a user must click a maliciously crafted link from an attacker.
## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Microsoft | Microsoft Exchange Server 2013 Cumulative Update 21 | | [KB4459266](https://patchblox.com/security/data/fix/microsoft/kb4459266.md) | Oct 9, 2018 | | Microsoft | Microsoft Exchange Server 2016 Cumulative Update 10 | | [KB4459266](https://patchblox.com/security/data/fix/microsoft/kb4459266.md) | Oct 9, 2018 | --- Data as of 2026-11-10T20:03:11Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo Free to use with attribution: show "Data: Patchblox Patch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.