Critical CVSS 8.1 EPSS 0.00852 2026-05 archive

Executive Summary

Heap-based buffer overflow in Microsoft Defender allows an unauthorized attacker to execute code over a network.

Overview

8.1
CVSS HIGH
Critical
MS Severity
Not Exploited
MS Exploit Status
Not Found
MS Exploit Likelihood
Category Remote Code Execution
Released May 12 2026
Last Updated May 12 2026
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.00852 — 0.53413 percentile
NVD CVSS 8.1 HIGH — matches MSRC

CVSS Vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
ATTACK VECTOR
Network
ATTACK COMPLEXITY
High
PRIVILEGES REQUIRED
None
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
High
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 7.1

EPSS Score

0.00852
probability of exploitation in the next 30 days
0.53413 percentile - updated 2026-06-21
View on FIRST.org

Affected Products

1 affected product
Product KB Article Severity Impact Restart Required
Microsoft Malware Protection Engine Release Notes (Security Update) Critical Remote Code Execution No

Patches

1 patch
Article Type Restart
Release Notes Security Update No

Known Exploits