Important CVSS 6.1 EPSS 0.01982 2019-09 archive

Executive Summary

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.

Overview

6.1
CVSS MEDIUM
Important
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
Category Spoofing
Released Sep 10 2019
Last Updated Sep 10 2019
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.01982 — 0.7848 percentile
NVD CVSS 6.1 MEDIUM — differs from MSRC

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
ATTACK VECTOR
Network
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
None
USER INTERACTION
Required
SCOPE
Changed

EPSS Score

0.01982
probability of exploitation in the next 30 days
0.7848 percentile - updated 2026-07-25
View on FIRST.org

Affected Products

4 affected products
Product KB Article Severity Impact Restart Required
Microsoft Exchange Server 2016 Cumulative Update 12 4515832 (Security Update) Important Spoofing Maybe
Microsoft Exchange Server 2016 Cumulative Update 13 4515832 (Security Update) Important Spoofing Maybe
Microsoft Exchange Server 2019 Cumulative Update 1 4515832 (Security Update) Important Spoofing Maybe
Microsoft Exchange Server 2019 Cumulative Update 2 4515832 (Security Update) Important Spoofing Maybe

Patches

1 patch
Article Type Restart
4515832 Security Update Maybe

Known Exploits

Acknowledgments

Abdulrahman Al-Qabandi