Critical EPSS 0.18161 2019-11 archive

Executive Summary

A remote code execution vulnerability exists in Microsoft Exchange through the deserialization of metadata via PowerShell. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the logged in user. Exploitation of this vulnerability requires that a user run cmdlets via PowerShell. The security update addresses the vulnerability by correcting how Exchange serializes its metadata.

Overview

Critical
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
Category Remote Code Execution
Released Nov 12 2019
Last Updated Nov 12 2019
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.18161 — 0.96835 percentile

EPSS Score

0.18161
probability of exploitation in the next 30 days
0.96835 percentile - updated 2026-06-20
View on FIRST.org

Affected Products

5 affected products
Product KB Article Severity Impact Restart Required
Microsoft Exchange Server 2013 Cumulative Update 23 4523171 (Security Update) Critical Remote Code Execution Maybe
Microsoft Exchange Server 2016 Cumulative Update 13 4523171 (Security Update) Critical Remote Code Execution Maybe
Microsoft Exchange Server 2016 Cumulative Update 14 4523171 (Security Update) Critical Remote Code Execution Maybe
Microsoft Exchange Server 2019 Cumulative Update 2 4523171 (Security Update) Critical Remote Code Execution Maybe
Microsoft Exchange Server 2019 Cumulative Update 3 4523171 (Security Update) Critical Remote Code Execution Maybe

Patches

1 patch
Article Type Restart
4523171 Security Update Maybe

Known Exploits

Acknowledgments

Pham Van Khanh from Viettel Cyber Security