Important CVSS 5.9 EPSS 0.00297 2026-03 archive

Executive Summary

Insufficient verification of data authenticity in Windows App Installer allows an unauthorized attacker to perform spoofing over a network.

Overview

5.9
CVSS MEDIUM
Important
MS Severity
Not Exploited
MS Exploit Status
Exploitation Unlikely
MS Exploit Likelihood
Category Spoofing
Released Mar 10 2026
Last Updated Mar 10 2026
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.00297 — 0.21128 percentile
NVD CVSS 5.9 MEDIUM — matches MSRC

CVSS Vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C
ATTACK VECTOR
Network
ATTACK COMPLEXITY
High
PRIVILEGES REQUIRED
None
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
None
INTEGRITY
High
AVAILABILITY
None
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 5.2

EPSS Score

0.00297
probability of exploitation in the next 30 days
0.21128 percentile - updated 2026-06-21
View on FIRST.org

Affected Products

1 affected product
Product KB Article Severity Impact Restart Required
Windows App Client for Windows Desktop (Security Update) Important Spoofing Maybe

Patches

1 patch
Article Type Restart
Security Update Maybe

Known Exploits

Acknowledgments

Zoltan Harmath with Microsoft